During the "Hindi Sad Diamonds" scene (The elaborate musical number from "Spectacular, Spectacular") Harry Ziegler is seated facing up-stage (for those of you not working in the theater, up-stage is the part of the stage furthest from the audience). In a close up shot he turns and looks over his shoulder at the Duke, and the camera cuts to a wide shot from above the audience, where we can see him facing foward again. Then the camera cuts back to the close up and he's facing the Duke again. Given the hyper active editing this whole movie uses, it's easy to miss.