I’m having the same issue. Multiple worlds that I haven’t opened since 2016 / 2017. One world wasn’t as old, but experiences the same issue.
This is not the same issue as MCPE-37926, that issue states "In The 1.7.0.9 beta when you go to your skins and choose a custom skin or change you have to restart minecraft so reopen it to see how you look, this is atiny annoying since you have to reopen minecraft everytime you change your skin."
This issue is not the same, at all. It is affecting me as well, since the 1.12 update. Please do not mark as resolved.
iPhone 11 Pro Max, iOS 14.0.1, Bedrock 1.16.50. Phone gets way too hot. When playing while plugged into an 18W charger, the battery will only maintain its current level. When unplugged, forget about it. The phone will be dead in about an hour.