Player can't loot themselves

I run a PVE server and my players are having issues looting themselves and sometimes boxes in pvp raids. It only allows you to grab 1 item at a time. I use TruePVE and Prevent looting. I've been on servers that have these plugins and they didn't have this issue. Was hoping you could point me in a direction.

I don't recall what caused this for the last person with this issue. I think it was a plugin altering stacksizes.