Hello and thank you for your work!

Seems that sometimes, not always, items that zombies pick up are shown on HUD as if the player had looted them.

That makes sense. 1.17 is the only supported version atm, if the problem occurs there as well please reopen this issue.

As it turns out, this is less a bug and more a compatibility request:

The problem happens when an entity loots an item while it is not rendered, because PickUpNotifier shows the looting as if it was yours. This happens with mods that cull entities, like Entity Culling or Dynamic Stealth.