It is right after the Godfather is shot in front of the market and Michael has come home to be with the family. He goes to see Kay (Diane Keaton) at her hotel and has dinner with her. Right before he gets up to leave, look at her wine glass, its almost empty. A split second later it has been filled, without either of them filling it. Michael then goes to see his father at the hospital. I don't understand how this would happen in such a short scene.