I wish I'd read the discussion before going down the same road Hugo did to prove what I believed I saw up front. I've made the mistake too many times of including an unqualified, invalid inner query field that was a valid outer query field and getting unexpected results, but not an error. I felt that before I responded I should verify that what I thought I saw was in fact the error I believed it to be. That was a waste of 5 minutes. (So I figured I'd waste a few more actually posting this response) 🙂