Star Wars Episode 3: Revenge of the Sith - Mace Approaches Twice
Mace Windoo has just had a fight with Palpatine, who is lying on the floor by the window. Mace moves right up to him and points his light sabre right up to his face. A few seconds later Anakin runs in, and Mace is back a few paces, and is only now stepping close to Palpatine.
I recently saw the movie again with the director's commentary on (which I highly recommend) and there is no mention that there is a lapse of time in which Anakin walks in right before Mace is menacing Palpatine with his lightsaber. Therefore, I agree that there are two distinct shots in which Mace approaches Palpatine. It is a true slip-up.