Looks like the old "Black Poly" problem, DS has always had a problem with it's internal triangulating of some polygon shapes, it does it badly enough so that the normals no longer work and turn the poly black when they are applied, 3 vertices in or almost in a row in a quad or ngon will cause this.

Looking at the picture and location & shape of that poly, I'd say that was PT-Vicki's leg (or her little sister) as she has that exact same problem in the same place, but Laura doesn't.