Multiplayer issues

I bought this game for my children to play, but the game desyncs upon death and doesn't allow any revival besides just quitting to the desktop and restarting the entire thing. We have run into issues with picking up items where players swap characters randomly like 3rd player swaps to 1st or simply controls both characters with one person's input. Also, if anyone joins the game while in the initial lobby screen, the UI to begin to play just disappears and the only thing to do, again, is quit to desktop. The game is fun without these glaring problems, but we can't even make it out of the first area without one of these problems popping up.