Continuity mistake: In the scene before Patton hears the news of getting relieved of command, he is walking with his NCO aide George, who is wearing E6 rank on his shirt. In the following scene while getting ready for bed, the same sergeant is now wearing E5 rank.
Continuity mistake: At the battle of Edgehill when Crowell's cavalry and Prince Rupert's cavalry are in the middle of a melee and you can see a wound on Crowell's left arm, the same wound he receives at Naseby. It is clear that the scene was meant to be used for the battle of Naseby but was cut and used at Edgehill.
Continuity mistake: Henry Miller at the beginning of the movie is mooching a few Francs to go out with his wife who just arrived in town. As he is trying to get a few from Boris, Mona's hair keeps changing position in front or behind her shoulders.