Character mistake: Stoddard in class says the founding document of the country can be added to with amendments. Pompey says it is the constitution written by Thomas Jefferson. Stoddard says 'declaration of independence'. Pompey was right, Stoddard incorrectly corrected him. It IS the constitution. The declaration can't be added to with amendments.
Character mistake: On the journey to meet Prince Feisal, Lawrence is offered food by his guide and accepts using his left hand. This would have been considered an insult as Arabs always eat using the right hand. The historical Lawrence would have known better. He had spent many years in the Middle East before the war.
Character mistake: During the press conference the Secretary of Defense yells at Senator Iselin "Where is the Sergeant-at-Arms? Throw that man of out here!" The problem is that "Sergeant-at-Arms" is a congressional post and that is not a position that would exist at the Defense Department (the Pentagon), nor would the Secretary of Defense hold a press conference in the Capitol (where someone who has that title would be).
Character mistake: In the opening scene when John Wayne calls the other truck, the response is "go ahead John", not Sean.
Suggested correction: I listened several times and I heard "Sean" every time.
Character mistake: According to the subtitles, when the landings begin General Marcks asks his aide to get General Pemsel at 5th Army on the phone. Pemsel was chief of staff of 7th Army, as the caption correctly states when he first appears. 5th Army was disbanded in 1939.