Help with players duping items

Hey, I have a server with friends running Paper 122 for 1.14.3, plugins: AuctionHouse-1.7.6, ChestShop, EssentialsX-, LuckPerms-Bukkit-4.4.1, Shopkeepers-2.7.2, and Vault.

If I leave the server running for about a day, players will become able to pickup items in their inventory, and have a copy held and another in their inventory. I can’t find any events causing this. This effects players server wide. Not sure if this is a plugin issue or a Paper issue.

Update auction house, see if any end portal dupes are working and also interrogate a player duping. Tell them you will ban them unless they tell you how they duped, once they tell you just ban all the abusers. That’s what I’ve done in the past to find out how they are doing it.