I am playing on Nintendo switch's bedrock edition and I don't have microsoft account (if it's somehow related to this). If I remember correctly this problem started when 1.16.20/piglin brute update came out.

Almost everytime I make a new custom skin I can play with it normally until I go to Nintendo switch's main menu and close the software. Then when I start minecraft again my custom skin has now suddenly changed. For example: it has Steves skin color instead of the one I made or it has Alex's hair instead of the hair I made and sometimes my custom skin has changed completely to Steve/Alex. In other words: When I enter to minecraft my custom skin looks more like Steve/Alex.

Expected result:
I make a custom skin and then I save it. I quit the game and come back and the custom skin has not changed at all.

Actual result:
I make a custom skin and then I save it. I quit the game and come back and the custom skin I just made looks more like Steve/Alex.

How to reproduce:
1) Make a custom skin
2) Go to main menu and close the software
3) Come back to minecraft and you see the result.

I haven't used custom skins for long time so I really hope this will be fixed. I also couldn't find the exact same issue so I am sorry if this has already reported.