--- a/dom/html/HTMLTrackElement.cpp
+++ b/dom/html/HTMLTrackElement.cpp
@@ -358,16 +358,17 @@ HTMLTrackElement::BindToTree(nsIDocument
 void
 HTMLTrackElement::UnbindFromTree(bool aDeep, bool aNullParent)
 {
   if (mMediaParent && aNullParent) {
     // mTrack can be null if HTMLTrackElement::LoadResource has never been
     // called.
     if (mTrack) {
       mMediaParent->RemoveTextTrack(mTrack);
+      mMediaParent->UpdateReadyState();
     }
     mMediaParent = nullptr;
   }
 
   nsGenericHTMLElement::UnbindFromTree(aDeep, aNullParent);
 }
 
 uint16_t

--- a/dom/media/TextTrack.cpp
+++ b/dom/media/TextTrack.cpp
@@ -258,16 +258,17 @@ TextTrack::SetReadyState(TextTrackReadyS
   if (!mTextTrackList) {
     return;
   }
 
   HTMLMediaElement* mediaElement = mTextTrackList->GetMediaElement();
   if (mediaElement && (mReadyState == TextTrackReadyState::Loaded||
       mReadyState == TextTrackReadyState::FailedToLoad)) {
     mediaElement->RemoveTextTrack(this, true);
+    mediaElement->UpdateReadyState();
   }
 }
 
 TextTrackList*
 TextTrack::GetTextTrackList()
 {
   return mTextTrackList;
 }