A multiplayer bug that creates a second character on the same account

Players 2-4 on local play recently has been having an issue that seems to create a fresh file even though the player, same account, has played on the world perviously. This creates a new character who loses items the player had in their inventory and loses control over pets tamed, but whatever the player built or created stays in the world. Minecraft also switches between the two files at random, the only constant being that on the second playthrough the second file is created. Player 1 is never effected. Other problems that I'm not sure is connected to the issue is that sometimes pervious skins that we've paid for is unaccessible and the game becomes super laggy at random times. Any feedback would be appreciated!

Edit: I forgot to include that this happens with split screen local play, I do not know if this effects online with players playing on different systems