Can't Change My Skin!

[DtGubs]

Been playing on the 1.12.2 version of forge for a bit, and noticed I can't at all change my skin. It's locked to a certain one, and only when I play on a forge version of 1.12.2. Any other version of 1.12.2 works just fine and I can change my skin normally.
I've tried wiping all files related to Forge 1.12.2 and redownloading it, but to no avail. Any help is appreciated 👍

Edited May 11, 2022 by DtGubs
Clarification