Current Realms world crashes occassionally when returning from the Nether into the Overworld, but has only happened at one of three nether portals and never on the way into the nether. Sound continues, game experiences extreme slow down and can recover. If I can see screen i move forawrd and wait  for game to catch up so I am not switching back and forth. If I do not move the transport sound occurs a couple times before disconecting or crashing. One of these times I had the Realm revert about 10-15 minutes once I reconnected.