I'd be really surprised if there were any internal patches, but I'll check to be sure. Will check normals. (I would have had to have done something really goofy)
There is no material on the skin, and the only surface attribute I've set is is diffuse color. I've got a decal for the eyebrows of course.
I'll try rendering from a different camera. I did move this camera and the problem didn't go away
I'll also try turning off hair, removing decals.
Sorry, haven't got a clue what SSS is.
Will post some results later today
(P.S. Thanks for the nice feedback on the render).