I can't upload a screen recording with the attachment size limit, but in the screenshot you can see the idea. I equipped a skin from a pack I imported earlier and it saved as steve instead of the skin.
I've been having the same issue since 1.17.30. I'm on iOS but I'm guessing it's doing this across platforms. Imported skins aren't saving properly. You can import the pack and see it in game just fine, but when you go to equip a custom skin that wasn't from the marketplace, it keeps saving as either steve or alex. To clarify, marketplace skins and skins imported from photos still work okay, it's just the imported skin packs that seem to be affected by this bug.
I've had the same issue consistently after this update. I have a few imported skin packs on my device, and none of them have been working. I'll hit "equip" on the skin but it always saves it as alex or steve. A friend I asked said the message when I changed skins was "____ edited character appearance", even though I was choosing a completely custom skin from the other tab. The import feature for single skins still works alright, but it's not ideal for me.
I'm currently having this issue on iOS