When I join another players world in split screen mode I lose all of my experience points as well as all of my inventory. I have hard reset my Xbox as well as deleted the game and re-installed it. Its as if I never once played in that world before. I also can't interact with any of my pets that I have in that world. My avatars skins don't transfer into that world or ever save. So the next time I sign into that world I have to change my avatars skin again. I have also unplugged and plugged the Xbox back in to see if that helps. I have also tried offline mode on Xbox but I can't think of any other action that would help get my experience and items back in that players world.