When Mrs Li enters Klinger's office carrying a pitch fork, the fork has 4 crooked prongs. Moments later the fork has 5 straight prongs.
Potter says that every bill has a president when referring to the money the dead soldier had. But one of the bills is a 100 dollar bill which has a portrait of Benjamin Franklin, who was never president.
When Potter and Margaret are talking to Mrs. Li, Loretta Swit's fingernails can be seen to be an inch long. No nurse, especially a head nurse, would have fingernails that long.
When performing CPR on Hastings, a reflexive wink is visible as opposed to movements caused by the procedure.
About 20 minutes in, when Father Mulcahy is playing piano and talking, his fingers do not actually press any of the keys, yet there is the sound of a piano being played.