diff --git a/lib/player.js b/lib/player.js
index a837c4c56..c86988463 100644
--- a/lib/player.js
+++ b/lib/player.js
@@ -1090,6 +1090,9 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
     /** @private {?shaka.text.SpeechToText} */
     this.speechToText_ = null;
 
+    /** @private {!Set<!Promise>} */
+    this.pendingExtraTrackPromises_ = new Set();
+
     // Even though |attach| will start in later interpreter cycles, it should be
     // the LAST thing we do in the constructor because conceptually it relies on
     // player having been initialized.
@@ -1657,6 +1660,8 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
         this.speechToText_.disable();
       }
 
+      this.pendingExtraTrackPromises_.clear();
+
       if (this.video_) {
         // The life cycle of tracks that created by addTextTrackAsync() and
         // their associated resources should be the same as the loaded video.
@@ -3071,6 +3076,7 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
     this.streamingEngine_.applyPlayRange(
         this.config_.playRangeStart, this.config_.playRangeEnd);
 
+    await this.waitForPendingExtraTrackPromises_();
     this.fullyLoaded_ = true;
 
     this.dispatchEvent(shaka.Player.makeEvent_(
@@ -3554,6 +3560,7 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
       }
     }
 
+    await this.waitForPendingExtraTrackPromises_();
     this.fullyLoaded_ = true;
   }
 
@@ -6815,135 +6822,143 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
    * @return {!Promise<shaka.extern.TextTrack>}
    * @export
    */
-  async addTextTrackAsync(uri, language, kind, mimeType, codec, label,
+  addTextTrackAsync(uri, language, kind, mimeType, codec, label,
       forced = false) {
-    if (this.loadMode_ != shaka.Player.LoadMode.MEDIA_SOURCE &&
-        this.loadMode_ != shaka.Player.LoadMode.SRC_EQUALS) {
-      shaka.log.error(
-          'Must call load() and wait for it to resolve before adding text ' +
-          'tracks.');
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.RECOVERABLE,
-          shaka.util.Error.Category.PLAYER,
-          shaka.util.Error.Code.CONTENT_NOT_LOADED);
-    }
-
-    if (kind != 'subtitles' && kind != 'captions') {
-      shaka.log.alwaysWarn(
-          'Using a kind value different of `subtitles` or `captions` can ' +
-          'cause unwanted issues.');
-    }
-
-    if (!mimeType) {
-      mimeType = await this.getTextMimetype_(uri);
-    }
-
-    let adCuePoints = [];
-    if (this.adManager_) {
-      adCuePoints = this.adManager_.getCuePoints();
-    }
-
-    if (this.loadMode_ == shaka.Player.LoadMode.SRC_EQUALS) {
-      const device = shaka.device.DeviceFactory.getDevice();
-      if (forced && device.getBrowserEngine() ===
-          shaka.device.IDevice.BrowserEngine.WEBKIT) {
-        // See: https://github.com/whatwg/html/issues/4472
-        kind = 'forced';
+    const p = (async () => {
+      if (this.loadMode_ != shaka.Player.LoadMode.MEDIA_SOURCE &&
+          this.loadMode_ != shaka.Player.LoadMode.SRC_EQUALS) {
+        shaka.log.error(
+            'Must call load() and wait for it to resolve before adding text ' +
+            'tracks.');
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.RECOVERABLE,
+            shaka.util.Error.Category.PLAYER,
+            shaka.util.Error.Code.CONTENT_NOT_LOADED);
       }
-      const trackNode = await this.addSrcTrackElement_(uri, language, kind,
-          mimeType, label || '', adCuePoints);
-      if (trackNode.track) {
-        this.onTracksChanged_();
-        this.onTextChanged_();
-        return shaka.util.StreamUtils.html5TextTrackToTrack(
-            trackNode.track, this.textDisplayer_.isTextVisible());
+
+      if (kind != 'subtitles' && kind != 'captions') {
+        shaka.log.alwaysWarn(
+            'Using a kind value different of `subtitles` or `captions` can ' +
+            'cause unwanted issues.');
       }
-      // This should not happen, but there are browser implementations that may
-      // not support the Track element.
-      shaka.log.error('Cannot add this text when loaded with src=');
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.RECOVERABLE,
-          shaka.util.Error.Category.TEXT,
-          shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_TEXT_TO_SRC_EQUALS);
+
+      if (!mimeType) {
+        mimeType = await this.getTextMimetype_(uri);
+      }
+
+      let adCuePoints = [];
+      if (this.adManager_) {
+        adCuePoints = this.adManager_.getCuePoints();
+      }
+
+      if (this.loadMode_ == shaka.Player.LoadMode.SRC_EQUALS) {
+        const device = shaka.device.DeviceFactory.getDevice();
+        if (forced && device.getBrowserEngine() ===
+            shaka.device.IDevice.BrowserEngine.WEBKIT) {
+          // See: https://github.com/whatwg/html/issues/4472
+          kind = 'forced';
+        }
+        const trackNode = await this.addSrcTrackElement_(uri, language, kind,
+            mimeType, label || '', adCuePoints);
+        if (trackNode.track) {
+          this.onTracksChanged_();
+          this.onTextChanged_();
+          return shaka.util.StreamUtils.html5TextTrackToTrack(
+              trackNode.track, this.textDisplayer_.isTextVisible());
+        }
+        // This should not happen, but there are browser implementations
+        // that may not support the Track element.
+        shaka.log.error('Cannot add this text when loaded with src=');
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.RECOVERABLE,
+            shaka.util.Error.Category.TEXT,
+            shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_TEXT_TO_SRC_EQUALS);
+      }
+
+      const ContentType = shaka.util.ManifestParserUtils.ContentType;
+
+      const seekRange = this.seekRange();
+      let duration = seekRange.end - seekRange.start;
+      if (this.manifest_) {
+        duration = this.manifest_.presentationTimeline.getDuration();
+      }
+      if (duration == Infinity) {
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.RECOVERABLE,
+            shaka.util.Error.Category.MANIFEST,
+            shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_TEXT_TO_LIVE_STREAM);
+      }
+
+      if (adCuePoints.length) {
+        const data = await this.getTextData_(uri);
+        const vvtText = this.convertToWebVTT_(data, mimeType, adCuePoints);
+        const blob = new Blob([vvtText], {type: 'text/vtt'});
+        uri = shaka.media.MediaSourceEngine.createObjectURL(blob);
+        mimeType = 'text/vtt';
+      }
+
+      /** @type {shaka.extern.Stream} */
+      const stream = {
+        id: this.nextExternalStreamId_++,
+        originalId: null,
+        groupId: null,
+        createSegmentIndex: () => Promise.resolve(),
+        segmentIndex: shaka.media.SegmentIndex.forSingleSegment(
+            /* startTime= */ 0,
+            /* duration= */ duration,
+            /* uris= */ [uri]),
+        mimeType: mimeType || '',
+        codecs: codec || '',
+        supplementalCodecs: '',
+        kind: kind,
+        encrypted: false,
+        drmInfos: [],
+        keyIds: new Set(),
+        language: language,
+        originalLanguage: language,
+        label: label || null,
+        type: ContentType.TEXT,
+        primary: false,
+        trickModeVideo: null,
+        dependencyStream: null,
+        emsgSchemeIdUris: null,
+        roles: [],
+        forced: !!forced,
+        channelsCount: null,
+        audioSamplingRate: null,
+        spatialAudio: false,
+        closedCaptions: null,
+        accessibilityPurpose: null,
+        external: true,
+        fastSwitching: false,
+        fullMimeTypes: new Set([shaka.util.MimeUtils.getFullType(
+            mimeType || '', codec || '')]),
+        isAudioMuxedInVideo: false,
+        baseOriginalId: null,
+      };
+
+      const fullMimeType = shaka.util.MimeUtils.getFullType(
+          stream.mimeType, stream.codecs);
+      const supported = shaka.text.TextEngine.isTypeSupported(fullMimeType);
+      if (!supported) {
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.CRITICAL,
+            shaka.util.Error.Category.TEXT,
+            shaka.util.Error.Code.MISSING_TEXT_PLUGIN,
+            mimeType);
+      }
+
+      this.manifest_.textStreams.push(stream);
+      this.onTracksChanged_();
+      this.onTextChanged_();
+      return shaka.util.StreamUtils.textStreamToTrack(stream);
+    })();
+
+    if (!this.fullyLoaded_) {
+      this.registerExtraTrackPromise_(p);
     }
 
-    const ContentType = shaka.util.ManifestParserUtils.ContentType;
-
-    const seekRange = this.seekRange();
-    let duration = seekRange.end - seekRange.start;
-    if (this.manifest_) {
-      duration = this.manifest_.presentationTimeline.getDuration();
-    }
-    if (duration == Infinity) {
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.RECOVERABLE,
-          shaka.util.Error.Category.MANIFEST,
-          shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_TEXT_TO_LIVE_STREAM);
-    }
-
-    if (adCuePoints.length) {
-      const data = await this.getTextData_(uri);
-      const vvtText = this.convertToWebVTT_(data, mimeType, adCuePoints);
-      const blob = new Blob([vvtText], {type: 'text/vtt'});
-      uri = shaka.media.MediaSourceEngine.createObjectURL(blob);
-      mimeType = 'text/vtt';
-    }
-
-    /** @type {shaka.extern.Stream} */
-    const stream = {
-      id: this.nextExternalStreamId_++,
-      originalId: null,
-      groupId: null,
-      createSegmentIndex: () => Promise.resolve(),
-      segmentIndex: shaka.media.SegmentIndex.forSingleSegment(
-          /* startTime= */ 0,
-          /* duration= */ duration,
-          /* uris= */ [uri]),
-      mimeType: mimeType || '',
-      codecs: codec || '',
-      supplementalCodecs: '',
-      kind: kind,
-      encrypted: false,
-      drmInfos: [],
-      keyIds: new Set(),
-      language: language,
-      originalLanguage: language,
-      label: label || null,
-      type: ContentType.TEXT,
-      primary: false,
-      trickModeVideo: null,
-      dependencyStream: null,
-      emsgSchemeIdUris: null,
-      roles: [],
-      forced: !!forced,
-      channelsCount: null,
-      audioSamplingRate: null,
-      spatialAudio: false,
-      closedCaptions: null,
-      accessibilityPurpose: null,
-      external: true,
-      fastSwitching: false,
-      fullMimeTypes: new Set([shaka.util.MimeUtils.getFullType(
-          mimeType || '', codec || '')]),
-      isAudioMuxedInVideo: false,
-      baseOriginalId: null,
-    };
-
-    const fullMimeType = shaka.util.MimeUtils.getFullType(
-        stream.mimeType, stream.codecs);
-    const supported = shaka.text.TextEngine.isTypeSupported(fullMimeType);
-    if (!supported) {
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.CRITICAL,
-          shaka.util.Error.Category.TEXT,
-          shaka.util.Error.Code.MISSING_TEXT_PLUGIN,
-          mimeType);
-    }
-
-    this.manifest_.textStreams.push(stream);
-    this.onTracksChanged_();
-    this.onTextChanged_();
-    return shaka.util.StreamUtils.textStreamToTrack(stream);
+    return p;
   }
 
   /**
@@ -6959,148 +6974,158 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
    * @return {!Promise<shaka.extern.ImageTrack>}
    * @export
    */
-  async addThumbnailsTrack(uri, mimeType) {
-    if (this.loadMode_ != shaka.Player.LoadMode.MEDIA_SOURCE &&
-        this.loadMode_ != shaka.Player.LoadMode.SRC_EQUALS) {
-      shaka.log.error(
-          'Must call load() and wait for it to resolve before adding image ' +
-          'tracks.');
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.RECOVERABLE,
-          shaka.util.Error.Category.PLAYER,
-          shaka.util.Error.Code.CONTENT_NOT_LOADED);
-    }
-
-    if (!mimeType) {
-      mimeType = await this.getTextMimetype_(uri);
-    }
-
-    if (mimeType != 'text/vtt') {
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.RECOVERABLE,
-          shaka.util.Error.Category.TEXT,
-          shaka.util.Error.Code.UNSUPPORTED_EXTERNAL_THUMBNAILS_URI,
-          uri);
-    }
-
-    const ContentType = shaka.util.ManifestParserUtils.ContentType;
-    const seekRange = this.seekRange();
-    let duration = seekRange.end - seekRange.start;
-    if (this.manifest_) {
-      duration = this.manifest_.presentationTimeline.getDuration();
-    }
-    if (duration == Infinity) {
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.RECOVERABLE,
-          shaka.util.Error.Category.MANIFEST,
-          shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_THUMBNAILS_TO_LIVE_STREAM);
-    }
-
-    const buffer = await this.getTextData_(uri);
-
-    const factory = shaka.text.TextEngine.findParser(mimeType);
-    if (!factory) {
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.CRITICAL,
-          shaka.util.Error.Category.TEXT,
-          shaka.util.Error.Code.MISSING_TEXT_PLUGIN,
-          mimeType);
-    }
-    const TextParser = factory();
-    const time = {
-      periodStart: 0,
-      segmentStart: 0,
-      segmentEnd: duration,
-      vttOffset: 0,
-    };
-    const data = shaka.util.BufferUtils.toUint8(buffer);
-    const cues = TextParser.parseMedia(data, time, uri, /* images= */ []);
-
-    const references = [];
-    for (const cue of cues) {
-      let uris = null;
-      const getUris = () => {
-        if (uris == null) {
-          uris = shaka.util.ManifestParserUtils.resolveUris(
-              [uri], [cue.payload]);
-        }
-        return uris || [];
-      };
-      const reference = new shaka.media.SegmentReference(
-          cue.startTime,
-          cue.endTime,
-          getUris,
-          /* startByte= */ 0,
-          /* endByte= */ null,
-          /* initSegmentReference= */ null,
-          /* timestampOffset= */ 0,
-          /* appendWindowStart= */ 0,
-          /* appendWindowEnd= */ Infinity,
-      );
-      if (cue.payload.includes('#xywh')) {
-        const spriteInfo = cue.payload.split('#xywh=')[1].split(',');
-        if (spriteInfo.length === 4) {
-          reference.setThumbnailSprite({
-            height: parseInt(spriteInfo[3], 10),
-            positionX: parseInt(spriteInfo[0], 10),
-            positionY: parseInt(spriteInfo[1], 10),
-            width: parseInt(spriteInfo[2], 10),
-          });
-        }
+  addThumbnailsTrack(uri, mimeType) {
+    const p = (async () => {
+      if (this.loadMode_ != shaka.Player.LoadMode.MEDIA_SOURCE &&
+          this.loadMode_ != shaka.Player.LoadMode.SRC_EQUALS) {
+        shaka.log.error(
+            'Must call load() and wait for it to resolve before adding image ' +
+            'tracks.');
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.RECOVERABLE,
+            shaka.util.Error.Category.PLAYER,
+            shaka.util.Error.Code.CONTENT_NOT_LOADED);
       }
-      references.push(reference);
+
+      if (!mimeType) {
+        mimeType = await this.getTextMimetype_(uri);
+      }
+
+      if (mimeType != 'text/vtt') {
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.RECOVERABLE,
+            shaka.util.Error.Category.TEXT,
+            shaka.util.Error.Code.UNSUPPORTED_EXTERNAL_THUMBNAILS_URI,
+            uri);
+      }
+
+      const ContentType = shaka.util.ManifestParserUtils.ContentType;
+      const seekRange = this.seekRange();
+      let duration = seekRange.end - seekRange.start;
+      if (this.manifest_) {
+        duration = this.manifest_.presentationTimeline.getDuration();
+      }
+      if (duration == Infinity) {
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.RECOVERABLE,
+            shaka.util.Error.Category.MANIFEST,
+            // eslint-disable-next-line @stylistic/max-len
+            shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_THUMBNAILS_TO_LIVE_STREAM);
+      }
+
+      const buffer = await this.getTextData_(uri);
+
+      const factory = shaka.text.TextEngine.findParser(mimeType);
+      if (!factory) {
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.CRITICAL,
+            shaka.util.Error.Category.TEXT,
+            shaka.util.Error.Code.MISSING_TEXT_PLUGIN,
+            mimeType);
+      }
+      const TextParser = factory();
+      const time = {
+        periodStart: 0,
+        segmentStart: 0,
+        segmentEnd: duration,
+        vttOffset: 0,
+      };
+      const data = shaka.util.BufferUtils.toUint8(buffer);
+      const cues = TextParser.parseMedia(data, time, uri, /* images= */ []);
+
+      const references = [];
+      for (const cue of cues) {
+        let uris = null;
+        const getUris = () => {
+          if (uris == null) {
+            uris = shaka.util.ManifestParserUtils.resolveUris(
+                [uri], [cue.payload]);
+          }
+          return uris || [];
+        };
+        const reference = new shaka.media.SegmentReference(
+            cue.startTime,
+            cue.endTime,
+            getUris,
+            /* startByte= */ 0,
+            /* endByte= */ null,
+            /* initSegmentReference= */ null,
+            /* timestampOffset= */ 0,
+            /* appendWindowStart= */ 0,
+            /* appendWindowEnd= */ Infinity,
+        );
+        if (cue.payload.includes('#xywh')) {
+          const spriteInfo = cue.payload.split('#xywh=')[1].split(',');
+          if (spriteInfo.length === 4) {
+            reference.setThumbnailSprite({
+              height: parseInt(spriteInfo[3], 10),
+              positionX: parseInt(spriteInfo[0], 10),
+              positionY: parseInt(spriteInfo[1], 10),
+              width: parseInt(spriteInfo[2], 10),
+            });
+          }
+        }
+        references.push(reference);
+      }
+
+      let segmentMimeType = mimeType;
+      if (references.length) {
+        segmentMimeType =
+            await this.getTextMimetype_(references[0].getUris()[0]);
+      }
+
+      /** @type {shaka.extern.Stream} */
+      const stream = {
+        id: this.nextExternalStreamId_++,
+        originalId: null,
+        groupId: null,
+        createSegmentIndex: () => Promise.resolve(),
+        segmentIndex: new shaka.media.SegmentIndex(references),
+        mimeType: segmentMimeType || '',
+        codecs: '',
+        supplementalCodecs: '',
+        kind: '',
+        encrypted: false,
+        drmInfos: [],
+        keyIds: new Set(),
+        language: 'und',
+        originalLanguage: null,
+        label: null,
+        type: ContentType.IMAGE,
+        primary: false,
+        trickModeVideo: null,
+        dependencyStream: null,
+        emsgSchemeIdUris: null,
+        roles: [],
+        forced: false,
+        channelsCount: null,
+        audioSamplingRate: null,
+        spatialAudio: false,
+        closedCaptions: null,
+        tilesLayout: '1x1',
+        accessibilityPurpose: null,
+        external: true,
+        fastSwitching: false,
+        fullMimeTypes: new Set([shaka.util.MimeUtils.getFullType(
+            segmentMimeType || '', '')]),
+        isAudioMuxedInVideo: false,
+        baseOriginalId: null,
+      };
+
+      if (this.loadMode_ == shaka.Player.LoadMode.SRC_EQUALS) {
+        this.externalSrcEqualsThumbnailsStreams_.push(stream);
+      } else {
+        this.manifest_.imageStreams.push(stream);
+      }
+      this.onTracksChanged_();
+      return shaka.util.StreamUtils.imageStreamToTrack(stream);
+    })();
+
+    if (!this.fullyLoaded_) {
+      this.registerExtraTrackPromise_(p);
     }
 
-    let segmentMimeType = mimeType;
-    if (references.length) {
-      segmentMimeType = await this.getTextMimetype_(references[0].getUris()[0]);
-    }
-
-    /** @type {shaka.extern.Stream} */
-    const stream = {
-      id: this.nextExternalStreamId_++,
-      originalId: null,
-      groupId: null,
-      createSegmentIndex: () => Promise.resolve(),
-      segmentIndex: new shaka.media.SegmentIndex(references),
-      mimeType: segmentMimeType || '',
-      codecs: '',
-      supplementalCodecs: '',
-      kind: '',
-      encrypted: false,
-      drmInfos: [],
-      keyIds: new Set(),
-      language: 'und',
-      originalLanguage: null,
-      label: null,
-      type: ContentType.IMAGE,
-      primary: false,
-      trickModeVideo: null,
-      dependencyStream: null,
-      emsgSchemeIdUris: null,
-      roles: [],
-      forced: false,
-      channelsCount: null,
-      audioSamplingRate: null,
-      spatialAudio: false,
-      closedCaptions: null,
-      tilesLayout: '1x1',
-      accessibilityPurpose: null,
-      external: true,
-      fastSwitching: false,
-      fullMimeTypes: new Set([shaka.util.MimeUtils.getFullType(
-          segmentMimeType || '', '')]),
-      isAudioMuxedInVideo: false,
-      baseOriginalId: null,
-    };
-
-    if (this.loadMode_ == shaka.Player.LoadMode.SRC_EQUALS) {
-      this.externalSrcEqualsThumbnailsStreams_.push(stream);
-    } else {
-      this.manifest_.imageStreams.push(stream);
-    }
-    this.onTracksChanged_();
-    return shaka.util.StreamUtils.imageStreamToTrack(stream);
+    return p;
   }
 
   /**
@@ -7115,123 +7140,131 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
    * @return {!Promise<shaka.extern.ChapterTrack>}
    * @export
    */
-  async addChaptersTrack(uri, language, mimeType) {
-    if (this.loadMode_ != shaka.Player.LoadMode.MEDIA_SOURCE &&
-        this.loadMode_ != shaka.Player.LoadMode.SRC_EQUALS) {
-      shaka.log.error(
-          'Must call load() and wait for it to resolve before adding ' +
-          'chapters tracks.');
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.RECOVERABLE,
-          shaka.util.Error.Category.PLAYER,
-          shaka.util.Error.Code.CONTENT_NOT_LOADED);
-    }
+  addChaptersTrack(uri, language, mimeType) {
+    const p = (async () => {
+      if (this.loadMode_ != shaka.Player.LoadMode.MEDIA_SOURCE &&
+          this.loadMode_ != shaka.Player.LoadMode.SRC_EQUALS) {
+        shaka.log.error(
+            'Must call load() and wait for it to resolve before adding ' +
+            'chapters tracks.');
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.RECOVERABLE,
+            shaka.util.Error.Category.PLAYER,
+            shaka.util.Error.Code.CONTENT_NOT_LOADED);
+      }
 
-    if (!mimeType) {
-      mimeType = await this.getTextMimetype_(uri);
-    }
+      if (!mimeType) {
+        mimeType = await this.getTextMimetype_(uri);
+      }
 
-    const ContentType = shaka.util.ManifestParserUtils.ContentType;
-    const seekRange = this.seekRange();
-    let duration = seekRange.end - seekRange.start;
-    if (this.manifest_) {
-      duration = this.manifest_.presentationTimeline.getDuration();
-    }
-    if (duration == Infinity) {
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.RECOVERABLE,
-          shaka.util.Error.Category.MANIFEST,
-          shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_CHAPTERS_TO_LIVE_STREAM);
-    }
+      const ContentType = shaka.util.ManifestParserUtils.ContentType;
+      const seekRange = this.seekRange();
+      let duration = seekRange.end - seekRange.start;
+      if (this.manifest_) {
+        duration = this.manifest_.presentationTimeline.getDuration();
+      }
+      if (duration == Infinity) {
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.RECOVERABLE,
+            shaka.util.Error.Category.MANIFEST,
+            shaka.util.Error.Code.CANNOT_ADD_EXTERNAL_CHAPTERS_TO_LIVE_STREAM);
+      }
 
-    const factory = shaka.text.TextEngine.findParser(mimeType);
-    if (!factory) {
-      throw new shaka.util.Error(
-          shaka.util.Error.Severity.CRITICAL,
-          shaka.util.Error.Category.TEXT,
-          shaka.util.Error.Code.MISSING_TEXT_PLUGIN,
-          mimeType);
-    }
+      const factory = shaka.text.TextEngine.findParser(mimeType);
+      if (!factory) {
+        throw new shaka.util.Error(
+            shaka.util.Error.Severity.CRITICAL,
+            shaka.util.Error.Category.TEXT,
+            shaka.util.Error.Code.MISSING_TEXT_PLUGIN,
+            mimeType);
+      }
 
-    const buffer = await this.getTextData_(uri);
-    const textParser = factory();
-    const time = {
-      periodStart: 0,
-      segmentStart: 0,
-      segmentEnd: duration,
-      vttOffset: 0,
-    };
-    const data = shaka.util.BufferUtils.toUint8(buffer);
-    const cues = textParser.parseMedia(data, time, uri, /* images= */ []);
-
-    const references = [];
-    for (const cue of cues) {
-      const reference = new shaka.media.SegmentReference(
-          cue.startTime,
-          cue.endTime,
-          () => [],
-          /* startByte= */ 0,
-          /* endByte= */ null,
-          /* initSegmentReference= */ null,
-          /* timestampOffset= */ 0,
-          /* appendWindowStart= */ 0,
-          /* appendWindowEnd= */ Infinity,
-      );
-      /** @type {shaka.media.SegmentReference.Metadata} */
-      const metadata = {
-        title: cue.payload,
-        images: [],
+      const buffer = await this.getTextData_(uri);
+      const textParser = factory();
+      const time = {
+        periodStart: 0,
+        segmentStart: 0,
+        segmentEnd: duration,
+        vttOffset: 0,
       };
-      reference.setMetadata(metadata);
-      references.push(reference);
+      const data = shaka.util.BufferUtils.toUint8(buffer);
+      const cues = textParser.parseMedia(data, time, uri, /* images= */ []);
+
+      const references = [];
+      for (const cue of cues) {
+        const reference = new shaka.media.SegmentReference(
+            cue.startTime,
+            cue.endTime,
+            () => [],
+            /* startByte= */ 0,
+            /* endByte= */ null,
+            /* initSegmentReference= */ null,
+            /* timestampOffset= */ 0,
+            /* appendWindowStart= */ 0,
+            /* appendWindowEnd= */ Infinity,
+        );
+        /** @type {shaka.media.SegmentReference.Metadata} */
+        const metadata = {
+          title: cue.payload,
+          images: [],
+        };
+        reference.setMetadata(metadata);
+        references.push(reference);
+      }
+
+      const chaptersMimeType = 'text/plain';
+
+      /** @type {shaka.extern.Stream} */
+      const stream = {
+        id: this.nextExternalStreamId_++,
+        originalId: null,
+        groupId: null,
+        createSegmentIndex: () => Promise.resolve(),
+        segmentIndex: new shaka.media.SegmentIndex(references),
+        mimeType: chaptersMimeType,
+        codecs: '',
+        supplementalCodecs: '',
+        kind: '',
+        encrypted: false,
+        drmInfos: [],
+        keyIds: new Set(),
+        language: language,
+        originalLanguage: language,
+        label: null,
+        type: ContentType.CHAPTER,
+        primary: false,
+        trickModeVideo: null,
+        dependencyStream: null,
+        emsgSchemeIdUris: null,
+        roles: [],
+        forced: false,
+        channelsCount: null,
+        audioSamplingRate: null,
+        spatialAudio: false,
+        closedCaptions: null,
+        accessibilityPurpose: null,
+        external: true,
+        fastSwitching: false,
+        fullMimeTypes: new Set([shaka.util.MimeUtils.getFullType(
+            chaptersMimeType, '')]),
+        isAudioMuxedInVideo: false,
+        baseOriginalId: null,
+      };
+
+      if (this.loadMode_ == shaka.Player.LoadMode.MEDIA_SOURCE) {
+        this.manifest_.chapterStreams.push(stream);
+      } else {
+        this.externalSrcEqualsChapterStreams_.push(stream);
+      }
+      this.onTracksChanged_();
+      return shaka.util.StreamUtils.chapterStreamToTrack(stream);
+    })();
+
+    if (!this.fullyLoaded_) {
+      this.registerExtraTrackPromise_(p);
     }
 
-    const chaptersMimeType = 'text/plain';
-
-    /** @type {shaka.extern.Stream} */
-    const stream = {
-      id: this.nextExternalStreamId_++,
-      originalId: null,
-      groupId: null,
-      createSegmentIndex: () => Promise.resolve(),
-      segmentIndex: new shaka.media.SegmentIndex(references),
-      mimeType: chaptersMimeType,
-      codecs: '',
-      supplementalCodecs: '',
-      kind: '',
-      encrypted: false,
-      drmInfos: [],
-      keyIds: new Set(),
-      language: language,
-      originalLanguage: language,
-      label: null,
-      type: ContentType.CHAPTER,
-      primary: false,
-      trickModeVideo: null,
-      dependencyStream: null,
-      emsgSchemeIdUris: null,
-      roles: [],
-      forced: false,
-      channelsCount: null,
-      audioSamplingRate: null,
-      spatialAudio: false,
-      closedCaptions: null,
-      accessibilityPurpose: null,
-      external: true,
-      fastSwitching: false,
-      fullMimeTypes: new Set([shaka.util.MimeUtils.getFullType(
-          chaptersMimeType, '')]),
-      isAudioMuxedInVideo: false,
-      baseOriginalId: null,
-    };
-
-    if (this.loadMode_ == shaka.Player.LoadMode.MEDIA_SOURCE) {
-      this.manifest_.chapterStreams.push(stream);
-    } else {
-      this.externalSrcEqualsChapterStreams_.push(stream);
-    }
-    this.onTracksChanged_();
-    return shaka.util.StreamUtils.chapterStreamToTrack(stream);
+    return p;
   }
 
   /**
@@ -9340,6 +9373,26 @@ shaka.Player = class extends shaka.util.FakeEventTarget {
       delete config['preferredVideoCodecs'];
     }
   }
+
+  /**
+   * @param {!Promise} p
+   * @private
+   */
+  registerExtraTrackPromise_(p) {
+    this.pendingExtraTrackPromises_.add(p);
+    p.finally(() => this.pendingExtraTrackPromises_.delete(p));
+  }
+
+  /**
+   * @return {!Promise}
+   * @private
+   */
+  async waitForPendingExtraTrackPromises_() {
+    if (!this.pendingExtraTrackPromises_.size) {
+      return;
+    }
+    await Promise.all([...this.pendingExtraTrackPromises_]);
+  }
 };
 
 /**
diff --git a/lib/queue/queue_manager.js b/lib/queue/queue_manager.js
index c81bb5083..c3e3308bb 100644
--- a/lib/queue/queue_manager.js
+++ b/lib/queue/queue_manager.js
@@ -224,11 +224,17 @@ shaka.queue.QueueManager = class extends shaka.util.FakeEventTarget {
       this.player_.configure(item.config);
     }
 
+    if (item.extraText?.length ||
+        item.extraThumbnail?.length ||
+        item.extraChapter?.length) {
+      this.eventManager_.listenOnce(this.player_, 'streaming', async () => {
+        await this.addExtraTracks_(item);
+      });
+    }
+
     await this.player_.load(assetUriOrPreloader, item.startTime, item.mimeType);
 
     this.preloadNext_ = null;
-
-    await this.addExtraTracks_(item);
   }
 
   /**