Async parse.com query not working on Android/iOS

When I try to make an asynchronous Parse.com request to fetch data, the task does not seem to get completed. T$$anonymous$$s works wit$$anonymous$$n the Unity Editor, but not when running on an Android or iOS device.

I had t$$anonymous$$s working until a few days ago, I re-arc$$anonymous$$tected my code a bit and been having trouble since then.

Here's my code snippet:

     public void GetFriendScores()
     {
         StartCoroutine (GetFriendsScoresCoroutine ());
     }
 
     IEnumerator GetFriendsScoresCoroutine()
     {
         Debug.Log("Started friends get scores coroutine");        
         
         //Assume these variables contain relevant information
         var ids = ............. (string list of facebook IDs)
                 
                 
         //Get a list of users who match the friend FB IDs
         var usersQuery = ParseObject.GetQuery ("FBUser").WhereContainedIn ("FB_ID", ids);
         
         //Use the user query result to find corresponding $$anonymous$$gh score rows
         var scoresQuery = ParseObject.GetQuery ("HiScores").WhereMatchesQuery ("User", usersQuery);
         var scoresQueryTask = scoresQuery.FindAsync ();
         
         Debug.Log("Started get scores task");
         w$$anonymous$$le (! (scoresQueryTask.IsCompleted))
             yield return null;
             
         Debug.List("Get scores task complete");
     }

The last line of Debug I see is "Started get scores task", and not$$anonymous$$ng after that.

When I run it in the editor, I get the correct data and the "Get Scores task complete" message.

Any idea what I might have missed? I'm using Parse 1.5.3 and can confirm that it was working before I re-wrote the code.