Things disappear after reopen saved world

Hi! I would like to report a problem in 1.17.40 alpha, Minecraft Pocket Edition. I have a word which I play almost 5 years and in some 1.17.x versions I lose some things after saving and reopen my world. The most common things I lose: boats, item frames (with the item in it), armor stand (with armor) and some mobs (rabbits, pigs, cows) as well. This world is a survival island so its very frustrating to lose things, especially hostile mobs.

I am using the original version of the game on my phone (Galaxy A50 with Android 11) without any mods and addons. 

Thank you for your attention!