After the update I got one of my worlds to play.  When I was done I went into the pause menu to save on quit. Only it didn't let me in the pause menu. It just loaded and loaded till I restarted my Minecraft. Your still able to walk around. At first I was like okay maybe my games glitched I'll try again later. Me and my friends got on later and it happened again only he wait longer then I did and it crashed his game. I hope this you resolve this soon because I'm afraid I'll loose progress if I don't save and quit and we've done a lot on the world.