If you rollback a player's inventory, and that player's inventory was full including armor and off-hand, then some of the full slots in that player's inventory will get deleted to make space for the armor and off-hand items. Therefore that player could lose valuable items.

To replicate:

1. Make your inventory full, with armor and off-hand filled
2. Clear inventory or get rid of items
3. Rollback your inventory

Version: 21.1

CoreProtect won’t/can’t delete items to add items. The issue is likely just that the inventory is being seen as full and items just aren’t being added.

Fixed here: 3011aec

Fix will be included in v21.2. I've also attached a patched v21.1 version with the fix for you.

CoreProtect-21.1b.jar.zip