WowAce

No errors thrown and so far haven't noticed any issues with sorting *other* than on my AH mule, but since an update or two ago sorting is not handling caged pets properly.  Mind you, it's never sorted them beyond "group all caged pets together" which is fine, but now it's leaving them in random clumps with other stuff in-between and it's doing so consistently.  As in, I'll switch the positions of two bags on my AH character and it will re-sort everything back into the same positions (again, pets aren't further sorted, so which pet is where might change but they'll generally be in the same locations).  All 10.0.2 compatible versions have this issue, but I can't remember if it predated that or not.  Also checked with just BankStack enabled, no change in behavior.

Image embed didn't work, posted a screenshot of my "Perfection already exists" inventory with caged pets highlighted over here: https://www.dropbox.com/s/oek56vsn8svxb9p/WoWScrnShot_111822_145744.jpg?dl=0

I too was having that same issue on my bank toon - I would hit sort and it would seem to re-arrange everything but the same pets weren't together.