allowSceneActivation only works once in the editor when trying to delay loading a scene.

I'm trying to delay reloading a level until after I'm done showing some animation. My code is basically:

 IEnumerator killPlayer(GameObject player) {
     AsyncOperation reload = Application.LoadLevelAsync(Application.loadedLevel);
     reload.allowSceneActivation = false;
     
     while (**<some condition>**) {          
       // Show the player dying, some animation, etc
       yield return null;
     }
     
     while (reload.progress < 0.9f) {
       yield return null;
     }
     
     reload.allowSceneActivation = true;
   }

As you can see, the key thing is the setting of allowSceneActivation to false so that even if the scene is done loading, it won't kill the current scene until eat least after my other animations are done (the first while loop). By the time the first loop is done, the next one potentially waits until we reached the infamous undocumented 90% and only then do I re-enable allowSceneActivation to finally load the scene.

When I try this in the editor, the first time around it works just fine. But after working once, it never again reloads the scene, because the second while never breaks, because the progress is stuck at 0.

Any thoughts?