I think I have this one...Your RayTrace light is causing this. When you change to Ray Trace, The "Shadow minimum Bias" should be reduced to .100 or less. Opposite direction from a normal spot. I would also kill everything in settings except; Use disp maps. RayTrace on. Cast shadows. Reset Pixel samples to 3 Reset post filter to 1 Min and Max texture, I'm not sure matters at this point. If you check focal distance, be aware that this one is one the time pigs from hell, so render to a tiny window until you have it just right. These settings did "Muted Portrait Comp2" at my gallery, if you want to see if you can deal with these choices.