Put it in Warehouse 1 and restart it and all the player items are gone.
Other warehouses do not cause this problem

I think I have to correct that it's the item that disappears when the player quits, not the restart.

Hello @MCSMallSoul! Sorry for the inconvenience.

Can you tell me which version of the plugin and Spigot/Paper are you using? There seems to be a problem with data management, but I'm having trouble reproducing the bug locally. I need as much info as possible, thank you