On Android, Minecraft 1.7.0.13, there are no slimes spawning, even in a flat world, in either single player or realm.
Very sorry to open this duplicate. I hate to do that. I did search for it though and couldn't find 😞
I'm also having this issue. The custom skin show as pure black when selecting it. And then it just switches beck to Alex.
Also happened to my villagers in multiple occasions. My trading hall is over 10 solid blocks underground, with no sky access anywhere around 50+ blocks, and they constantly turn into witches. I had to enable cheats in my world and disable the weather cycle. Found this youtube evidence as well: https://m.youtube.com/watch?v=jEAfxLnaiic