What's going on with this game?! I have a main world weighing 30 megabytes, from this day it loads for 3 minutes and crashes. Why is this happening? 
I can't do anything in the world, just fly for 15 seconds and that's it, the game crashes.
The classic world without mods and other things.
There is no such problem with the new worlds, their size can be more than 300 megabytes and everything works fine. 
When loading the world, the game clogs up all the RAM to failure! When the world finally loads, I exit and wait for the save, it takes just as long and the game crashes. The game also crashes when entering hell.

My respects to the development team, I would fire such people EVERY UPDATE IS BUGS AND LAGS it's already tired!!!

https://bugs.mojang.com/browse/MCPE-144019
A very similar problem.