The area you circled is a white colour which is recieving direct, yellow tinted lighting from the window in the background. The dress is a white material which is facing away from and not recieving direct lighting from the background. It's semi silhouetted and recieving secoundary 'bounced' lighting from from whatever surfaces are facing it.
If I was at home right now I could recreate the lighting conditions in the scene in 3ds Max or Unreal Engine or something.
But how can two dresses facing the same direction not both be receiving the same light?