What happend was Me and my Sister we're just mining and we use the trick: One block in the overworld is 8 blocks in the Nether. than after traveling the nether we went through the portal. i (the world maker) came out just fine but my Sister suffocated in a wall Example: Sister goes through portal Player suffocated. but this only happens with Windows 10 users. This also happend to another friend Using Windows 10.  Another thing that happens is That The player is stuck on "Generating world". and the only choice is to force quit the game.