Skins will not change in game.

When you try changing your skin in a world or even from the opening screen it remains the same until you leave the game. Me and my friends have been having this problem for a while, and we even have different types of phones (all iOS). This bug occurs with our own skins and with the skins that Minecraft provides. This has been a problem for a long time, but I was waiting until the new update to say something, and the bug was not fixed.