Your skin does not load on beta versions

As i said the bug exists in beta versions so i just put 1.12.2 because it's necessary to say the versions but any beta versions says that it doesn't exists. I know that mojang isn't responsible of resolving old minecraft bugs but i just ask them to spend a bit of their time at resolving this bug. It's not a bug that was resolved by making new versions it's a bug that it's created in the actual time but affected the old versions