For some reason when I leave my world the inventory wont save yet when I switch worlds it SOMETIMES saves. This is annoying because I loose my progress when I rejoin and it also allows for item duping because you can drop the item, leave, rejoin and now you have double. Video

I found this was happening to me only when disconnecting and rejoining the server. I found the issue to be cause by game mode profiles. If that is disabled it seems to fix the issue.

Similar to #354