This bug also appeared in the Android version after the update to 1.17. I use the Android version in Linux, but the results are the same.

The body of my custom skin changes each time I return to the main menu and is either randomly pixellated or striped with some colour. The actual skin is never shown.

I have not had any problems with this skin previously and if I change to 1.16 in the Linux Android launcher, the skin is fine.