Affects Version/s: Minecraft 1.8.8, Minecraft 1.13
Fix Version/s: None
If a world contains 2 player skulls, each of the same players UUID, but each with a different texture ID (Obtained at 2 different time periods), the client will show alternating skin textures on the skulls.
The root issue lies that the skin cache in the client checks by GameProfile which the equals method only checks by name and uuid.
So when the client looks at a skull after the 15s cache expires, it will get one of the skins, cache it, and use it for both.
The client should show the correct skin for each skull, and simplest way to do that is to make the texture id also part of the cache key.