--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -439,18 +439,19 @@ public:
       mMaster->StopPlayback();
     }
     mMaster->Reset();
     mMaster->mReader->ReleaseResources();
   }
 
   void Exit() override
   {
-    // Transfer the seek job so it is available to the next state.
-    mMaster->mQueuedSeek = Move(mPendingSeek);
+    // mPendingSeek is either moved in HandleDormant() or should be rejected
+    // here before transition to SHUTDOWN.
+    mPendingSeek.RejectIfExists(__func__);
   }
 
   State GetState() const override
   {
     return DECODER_STATE_DORMANT;
   }
 
   bool HandleDormant(bool aDormant) override;