We've also opened a ticket. We assumed this was a Facepunch issue last week, however skins are still not working. When trying to craft a skinned item we get "You don't have permission to use this skin, so crafting unskinned".
We've tried the same (unloading oxide, update/validate, removing all plugins, etc...) no effect.
I jumped on another Rust server and found that skins are working just fine elsewhere.
I'll wait to see what support has to say.