VSRO Grab pet sometimes "forgets" to grab

I am just playing in my local non-edited vsro server. In probably 2 out of 10 drops, pet forgets to grab. its not a specific item. sometimes it doesn't grab gold, sometimes quest piece, or just junk items.

Pet options are correct, and I am not using a bot. What could be the problem?

I know. It is a widely known issue although nobody really talks about it.
I doubt there is a fix for that. Perhaps a pet filter?