Crash when going back into game

I was playing Minecraft to build with redstone or survival. I then go to do other stuff like checking on twitter or watch youtube, and then turn off my device. Or I have to go somewhere with my parent by turning off my device after pressing the save and quit button (exiting my world). After that, I get back on my device and type in my pass code. I go back to minecraft app, then suddenly, It either went back to ipad home screen (crashed), or it went to back Mojang Logo, and then the Minecraft home screen. I have to go back to my survival world or my redstone world for a longer time than going back to survival or redstone world right after checking twitter or watching youtube, or when I get back on to my device. But, I am still able to play my world after this happens. This is annoying. Hopefully that's fixed soon.

Video here. Hopefully you got the idea of what am I talking about. https://www.youtube.com/watch?v=qHLkL-LOgD0