PullAsync Silently fails

I'm using .Net backend Azure Mobile Services on a Windows Phone app. I've added the offline services that Azure Mobile Services provides to the code for using SQLite. The app makes successful Push calls (I can see the data in my database and they exist in the local db created by Azure Mobile Offline Services). In PullAsync calls, it makes the right call to the Service (The table controller) and Service calculates the results and returns multiple rows from the database. However, the results are lost on the way. My client App is getting an empty Json message (I double checked it with fiddler).

  var contactQuery = _contactTable.Where(c => c.Owner == Service.UserId);
  await _contactTable.PullAsync("c0", contactQuery);
  var contacts = await _contactTable.Select(c => c).ToListAsync();

Any suggestion on how I can investigate this issue?