Equip Button not available on custom skin pack

On custom skin packs, the Equip button disapeard on skin packs

Beaware that this bug is with Custom skin packs, that means packs created by a player creating some files and putting it on the skin packs folder (eg.lang.JSON, skins.JSON Manifest.JSON) on the route:
(\AppData\Local\Packages\Microsoft.MinecraftUWP_~~\LocalState\games\com.mojang\skin_packs)