--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -1220,16 +1220,17 @@ DecodeMetadataState::OnMetadataRead(Meta
   mMetadataRequest.Complete();
 
   // Set mode to PLAYBACK after reading metadata.
   Resource()->SetReadMode(MediaCacheStream::MODE_PLAYBACK);
 
   mMaster->mInfo = Some(aMetadata->mInfo);
   mMaster->mMetadataTags = aMetadata->mTags.forget();
   mMaster->mMediaSeekable = Info().mMediaSeekable;
+  mMaster->mMediaSeekableOnlyInBufferedRanges = Info().mMediaSeekableOnlyInBufferedRanges;
 
   if (Info().mMetadataDuration.isSome()) {
     mMaster->RecomputeDuration();
   } else if (Info().mUnadjustedMetadataEndTime.isSome()) {
     RefPtr<Master> master = mMaster;
     Reader()->AwaitStartTime()->Then(OwnerThread(), __func__,
       [master] () {
         NS_ENSURE_TRUE_VOID(!master->IsShutdown());
@@ -1672,17 +1673,16 @@ ShutdownState::Enter()
   master->mNextPlayState.DisconnectIfConnected();
   master->mVolume.DisconnectIfConnected();
   master->mPreservesPitch.DisconnectIfConnected();
   master->mSameOriginMedia.DisconnectIfConnected();
   master->mMediaPrincipalHandle.DisconnectIfConnected();
   master->mPlaybackBytesPerSecond.DisconnectIfConnected();
   master->mPlaybackRateReliable.DisconnectIfConnected();
   master->mDecoderPosition.DisconnectIfConnected();
-  master->mMediaSeekableOnlyInBufferedRanges.DisconnectIfConnected();
   master->mIsVisible.DisconnectIfConnected();
 
   master->mDuration.DisconnectAll();
   master->mIsShutdown.DisconnectAll();
   master->mNextFrameStatus.DisconnectAll();
   master->mCurrentPosition.DisconnectAll();
   master->mPlaybackOffset.DisconnectAll();
   master->mIsAudioDataAudible.DisconnectAll();
@@ -1744,17 +1744,16 @@ MediaDecoderStateMachine::MediaDecoderSt
   INIT_MIRROR(mNextPlayState, MediaDecoder::PLAY_STATE_PAUSED),
   INIT_MIRROR(mVolume, 1.0),
   INIT_MIRROR(mPreservesPitch, true),
   INIT_MIRROR(mSameOriginMedia, false),
   INIT_MIRROR(mMediaPrincipalHandle, PRINCIPAL_HANDLE_NONE),
   INIT_MIRROR(mPlaybackBytesPerSecond, 0.0),
   INIT_MIRROR(mPlaybackRateReliable, true),
   INIT_MIRROR(mDecoderPosition, 0),
-  INIT_MIRROR(mMediaSeekableOnlyInBufferedRanges, false),
   INIT_MIRROR(mIsVisible, true),
   INIT_CANONICAL(mDuration, NullableTimeUnit()),
   INIT_CANONICAL(mIsShutdown, false),
   INIT_CANONICAL(mNextFrameStatus, MediaDecoderOwner::NEXT_FRAME_UNINITIALIZED),
   INIT_CANONICAL(mCurrentPosition, 0),
   INIT_CANONICAL(mPlaybackOffset, 0),
   INIT_CANONICAL(mIsAudioDataAudible, false)
 {
@@ -1800,17 +1799,16 @@ MediaDecoderStateMachine::Initialization
   mNextPlayState.Connect(aDecoder->CanonicalNextPlayState());
   mVolume.Connect(aDecoder->CanonicalVolume());
   mPreservesPitch.Connect(aDecoder->CanonicalPreservesPitch());
   mSameOriginMedia.Connect(aDecoder->CanonicalSameOriginMedia());
   mMediaPrincipalHandle.Connect(aDecoder->CanonicalMediaPrincipalHandle());
   mPlaybackBytesPerSecond.Connect(aDecoder->CanonicalPlaybackBytesPerSecond());
   mPlaybackRateReliable.Connect(aDecoder->CanonicalPlaybackRateReliable());
   mDecoderPosition.Connect(aDecoder->CanonicalDecoderPosition());
-  mMediaSeekableOnlyInBufferedRanges.Connect(aDecoder->CanonicalMediaSeekableOnlyInBufferedRanges());
 
   // Initialize watchers.
   mWatchManager.Watch(mBuffered, &MediaDecoderStateMachine::BufferedRangeUpdated);
   mWatchManager.Watch(mState, &MediaDecoderStateMachine::UpdateNextFrameStatus);
   mWatchManager.Watch(mAudioCompleted, &MediaDecoderStateMachine::UpdateNextFrameStatus);
   mWatchManager.Watch(mVideoCompleted, &MediaDecoderStateMachine::UpdateNextFrameStatus);
   mWatchManager.Watch(mVolume, &MediaDecoderStateMachine::VolumeChanged);
   mWatchManager.Watch(mPreservesPitch, &MediaDecoderStateMachine::PreservesPitchChanged);

--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -732,16 +732,19 @@ private:
   bool mSentFirstFrameLoadedEvent;
 
   // True if video decoding is suspended.
   bool mVideoDecodeSuspended;
 
   // True if the media is seekable (i.e. supports random access).
   bool mMediaSeekable = true;
 
+  // True if the media is seekable only in buffered ranges.
+  bool mMediaSeekableOnlyInBufferedRanges = false;
+
   // Track enabling video decode suspension via timer
   DelayedScheduler mVideoDecodeSuspendTimer;
 
   // Data about MediaStreams that are being fed by the decoder.
   const RefPtr<OutputStreamManager> mOutputStreamManager;
 
   // Media data resource from the decoder.
   RefPtr<MediaResource> mResource;
@@ -807,19 +810,16 @@ private:
   Mirror<double> mPlaybackBytesPerSecond;
 
   // True if mPlaybackBytesPerSecond is a reliable estimate.
   Mirror<bool> mPlaybackRateReliable;
 
   // Current decoding position in the stream.
   Mirror<int64_t> mDecoderPosition;
 
-  // True if the media is seekable only in buffered ranges.
-  Mirror<bool> mMediaSeekableOnlyInBufferedRanges;
-
   // IsVisible, mirrored from the media decoder.
   Mirror<bool> mIsVisible;
 
   // Duration of the media. This is guaranteed to be non-null after we finish
   // decoding the first frame.
   Canonical<media::NullableTimeUnit> mDuration;
 
   // Whether we're currently in or transitioning to shutdown state.