I mean, it literally is not the same. While the inventory gets wiped clean and the exp is gone in either problems. My problem is much more straightforward. She is seen as a second player, always in lan and there is no reverting back from that. They all have a problem with the player saves but none of them says anything about being seen as a different player. I'll post under that post as well (and it's a year old so i hope you are still considering it).
still a problem in 1.21.1
logged in a world that we used to play online while we were playing locally (so loaded it as lan) and as the second player joined his inventory was completely wiped clean. I already reported this problem in like 4 different places. This is becoming a nuisance because everytime the second player joins his inventory COULD be reset and i'd have to grind everything back again for the second player. It's the second time now this has happened.