Other mistake: In the early part of the movie, Rommel is addressing his Officers on the Atlantic Wall. The "mid-shots" and "close-ups" are shot against a back projection. Rommel turns to view the sea/horizon and the view is exactly the same as their "mid-shots". The effect is a horrendous "jump-cut".
Other mistake: During the French Commandoes' attack on the Ouistreham casino, the Germans spot commando units at a tower. A lookout gives the information to the cannon crew, but the cannon is aimed towards the target while the commanding officer is still confirming the information.