Revealing mistake: If you look closely at Billy Flynn in the musical number "All I Care About is Love", right at the end when he takes off the boxers, you can see that he is wearing underwear underneath them.
Revealing mistake: In the Atlanta party scene, we are supposed to believe it starts with a single long take. However there is a sneaky edit when Frank crosses the threshold of the room. He emerges at a slighty quicker pace and his hair is suddenly messed up. (01:10:35)
Suggested correction: There is nothing obvious in this scene that supports this. When he emerges on the other side, he bumps into his friend so suddenly that you can't tell if he was walking at a different pace. The reason his hair is messed up is because he bumps into his friend. He then yells at his friend, jerking his head around as he does so, which messes up his hair even further, which can be seen.
Even if it were true, it wouldn't qualify as a mistake. The shot may be intended to appear as a single shot, but that doesn't mean it's a mistake if it isn't.
Revealing mistake: In the scene with Leonard and Virginia at the train station, an electronic display can briefly be seen hanging from the roof above Leonard's head.
Revealing mistake: When Elizabeth returns to St. Benedict's after 25 years she hasn't aged a bit. (01:04:10)
Revealing mistake: When Madonna and Greenwood sit at a table having lunch (in company), Madonna is holding a cigarette while the guy to her right tiredly rubs his eyes, and a fur-covered microphone dangles in plain view from the top of the screen.
Revealing mistake: When Bob Crane was playing drums in the club, the night that he told Patti he and John were going out - he CLEARLY isn't playing to the beat, as you can hear drum fills, and he just playing as hitting the drum once with his left stick.
Revealing mistake: In the scene where Joey is arrested, they handcuff him. When the police pulls him on his feet, you can see that the handcuffs are not on, but the officer is just holding them. (01:36:05)
Revealing mistake: In the opening scene right after she's put in the truck, she is lying on the bed looking in a mirror above her and her earrings are hanging parallel to the ground as though she was standing. (00:02:12)
Revealing mistake: During the love scene two shots of Cheryl Ladd's legs are shown. But they're not hers as they're tanned and have firmer muscle. Clearly her double's legs.
Revealing mistake: When Dormer fails to pursue Finch during the log chase scene, he climbs out of the water by a ladder. If you look at Dormer's back as he gets out of the water onto the dock you can see an outline of the life jacket Pacino wore to film the scene. You can see the outline again when he turns around and walks up the walkway. (01:00:49 - 01:01:11)