For at least the last month or more, in all areas, no matter what pets are used, after using auto combat for probably 10 minutes or more, pets will refuse to loot certain chests and it just keeps flashing "target does not exist". Even after looting all chests in the area manually, it keeps doing it. The only fix is to zone out of the area and come back. Then several minutes later it will start doing it again. No telling how many chests have been lost because of this bug when you're not there babysitting the game. This is a well known issue many many people have expressed having and it still goes ignored.

PLEASE FIX THIS!!!

I have found in iPadOS that if you tap on a pet to open the pet window and immediately close it, they will start picking up again.  Sometimes it takes doing this twice.   They seem to stop picking up after a sorcery fragment is dropped.  I reported pet issue just before last patch along with "Authentication KEY does not match" and a few other things like auto play getting disabled in Black Spirit Mode, got a response back saying they should be fixed with the update but haven't seen any fix yet. 

one month :))))) 

The Sorcery Fragment event is over, but the bug remains. One pet seems to get stuck on a specific chest, while the others continue picking up.