I'm having the same issue. I play on Xbox with my daughter and my son will play on PC and join. He can still join my daughters world but when I try to do it in the same console, split screen it won't load my account. It will load the main account of the world twice for the split screen. I've tried all the obvious things, uninstalling minecraft, signing out accounts, assigning controllers to accounts, making a news Microsoft account. Nothing has worked. Frustrated.
I'm having the same issue. I play on Xbox with my daughter and my son will play on PC and join. He can still join my daughters world but when I try to do it in the same console, split screen it won't load my account. It will load the main account of the world twice for the split screen. I've tried all the obvious things, uninstalling minecraft, signing out accounts, assigning controllers to accounts, making a news Microsoft account. Nothing has worked. Frustrated.