Skins fail to load

So whenever I load up minecraft it opens to the main menu and if I had a skin from a skin pack equipped it would show either Steve or Alex and If I go into the profile menu the characters fail to load if they are from any skin pack, although custom skins made from the customisation menu will load. This used to happen with 1.14/1.15 sometime but was recently fixed I believe as I have not had the problem for a while until updating to 1.16.20. Please fix this again