Hi,
I tried it in TG3 and had problems as well. I opened it in Blender and messed about with it a bit (Recalculated normals, flipped normals) and exported as an OBJ with normals and the triangulate faces option switched on. I'm not sure what did the trick exactly, but that seems to have worked so it looks as expected in TG3. The usual advice with problematic OBJs seems to be to run it through PoseRay. If you search the forum it might turn up some advice about that, I haven't used it myself.
At a guess the problem was either down to normals or polys with more than 4 sides.
Regards,
Jo