Faulty Save and Quit button
I have noticed that the save and quit button doesn't work anymore. It quits, but doesn't save. I noticed this bug only occuring when I have done tons of digging and building, both singleplayer and multiplayer(I also noticed the game tends to freeze when a friend joins) both creative and survival. When I pause and tap "Save and Quit" it appears to register. The stays on the same pause screen for about 2-5 minutes before crashing. When i restart MCPE and open my world. Nothing saved. It looks just the same as if i never built anything or mined. Also this only happens in an infinite world. Never on an old nor flat.

Lag, Lag, Lag
I have tried to place wither skulls in the nether, but the entire game freezes and my game doesn't respond. Then i can move but I can't interact with anything. The gamemode is and still was survival. not even the pigman is trying to kill me.