Client loads cape texture before skin texture causing transparency.

If a player sets their skin to the texture file of a cape (most commonly migrator) and joins a multiplayer environment, the client will load the migrator cape before it loads the skin of the player, since the cape's texture is cached, the client ignores the alpha pixels check on player skins, this causes players using a "cape texture" as a skin to appear with transparent pixels.

 

However, if the client loads the skin texture before the cape, then the cape texture is cached with blanked alpha pixels, making capes appear buggy.

 

(Reproduced transparent skin & buggy cape on 1.8.9, reproduced buggy cape but not skin on 1.19+)