I’ve made this post a while ago and it says the issue was resolved even though it has yet to be fixed.

Since after the 1.16.210 update, there’s been a glitch where (some) custom skins simply don’t change to another. I’ll choose a custom skin and it’ll say that “The Character has been saved” but it remains the previous skin I had on. If I change my skin from a slot that says “Create Character,” and not one that already has a skin, it will change to a Steve or an Alex skin. This has been going on for a couple months now and it’s getting pretty obnoxious.

Check the attached video for a clearer image of what I’m trying to explain.

To reproduce: you will need 2 skin packs
1. Select skin from skin pack 1, exit skin editing screen
2. Reenter selecting a skin from skin pack 2 exit skin editing screen

Observed Results: Minecraft does not set the skin to the one you selected
Expected Results: Minecraft sets the skin you selected

for the 2nd part of this issue

1. Create a new character and select a skin
2. Exit the skin menu

Observed Results: Minecraft sets the skin to steve or alex
Expected Results: Minecraft sets the skin you selected

Video: https://www.youtube.com/watch?v=VOr2u0Ik5ow