Hmm my only problem with this would be the big fat fake specular highlight on the floor in the middle... in reality that area would dark, a reflection of the wall behind the sofa and the actual lower surface of the sofa.. I think you should remove specularity on the floor and only use reflections!
I can see what you mean, I think it's the area light behind the back wall poking through. But, with my camera angle, I can not get the underside of the chair or the wall if you really look at it. I might rerender without spec on the floor, but not changing the cam angle