--- a/content/media/MediaStreamGraph.cpp
+++ b/content/media/MediaStreamGraph.cpp
@@ -1005,19 +1005,17 @@ MediaStreamGraphImpl::PrepareUpdatesToMa
       if (!stream->MainThreadNeedsUpdates()) {
         continue;
       }
       StreamUpdate* update = mStreamUpdates.AppendElement();
       update->mGraphUpdateIndex = stream->mGraphUpdateIndices.GetAt(mCurrentTime);
       update->mStream = stream;
       update->mNextMainThreadCurrentTime =
         GraphTimeToStreamTime(stream, mCurrentTime);
-      update->mNextMainThreadFinished =
-        stream->mFinished &&
-        StreamTimeToGraphTime(stream, stream->GetBufferEnd()) <= mCurrentTime;
+      update->mNextMainThreadFinished = stream->mNotifiedFinished;
     }
     if (!mPendingUpdateRunnables.IsEmpty()) {
       mUpdateRunnables.MoveElementsFrom(mPendingUpdateRunnables);
     }
   }
 
   // Don't send the message to the main thread if it's not going to have
   // any work to do.