Discovered this bug today in 2/24/23, also saw some other people were having the same issue. I would log in to my partners world and we would both enter with empty inventory like we died and went back to starting spawn point. We decided to make a copy of the world and our stuff came back, and just decided to keep playing, but when I logged back into the extra copy. All of our stuff from our inventory was removed again. It's really annoying because the only time we get to play together this bug happened. We thought it was his Xbox or my switch but I think it's the game itself, since it's been happening to other people as well.