One of the more mysterious bugs currently on the PTR is the fact that Human Females (maybe others, but none I've noticed) transferred over to the PTR are having their faces swapped around. In the picture above, you can see that my Paladin has two different faces. The one on the left is from Live servers, the one on the Right is from the patch 3.1 test realm. It isn't happening to all characters, oddly. Just some of them. My Priest, who is also a Human Female, transferred just fine and has the same face she always does. Which happens to be the face my Paladin has on the PTR now. Funky.
It's a known issue, and I'm sure it'll go away long before this patch ever hits live realms, but it's a very curious bug. It was likely caused by something quite mundane, but it makes me wonder if they were working on something that caused faces to shift out of the numerical order they had before. Adding new skins, perhaps? Updating old ones? Maybe, maybe not.