Deliberate mistake: During the rumble scene there is a "Soc" whose clothes are completely dry and clean right before the Socs surrender. He's wearing a light blue shirt.
Deliberate mistake: When Cochran sabotages the Jet Ranger helicopter by loosening the nut on the bolt securing the linear actuator governor, the bolt is inserted in the wrong direction. The bolt should have been heads up to prevent it from falling out as it did causing the helicopter to crash. Moreover, the linear actuator is on the opposite of the engine from where Cochran disconnected it. (00:38:05)William Bergquist
Deliberate mistake: The shots of the prisoner skiff during the transport to the Sarlacc Pit are reversed. This can, for example, be seen as Chewie's bandolier is on the wrong side, and that Han's shirt is overlaying the wrong way.
Deliberate mistake: Eddie Murphy is giving his first party and tells everyone to leave. The valet holds all the coats in a perfect pile for the people to grab them as they leave. Although everyone rushes out of the party, it's very strange that the first person to leave takes the first coat, the second person the second coat and so on until the very last guest. No one stops to check if the coat they're taking is really theirs. (I guess it was shot this way to keep the good pace of the sequence). (00:43:55)Sacha
Deliberate mistake: The scene where Arnie takes Denis for a high-speed ride was obviously shot in a studio. Arnie throws an empty beer can out of a car doing 80+mph, so the window was rolled down - but his hair isn't ruffled at all. Alternatively, he used concrete as hairspray.
Deliberate mistake: When they arrive in Washington D.C., they are seen in a 1976 Dodge Dart taxicab, but the movie supposedly took place in 1974. There are several scenes where many cars used in the movie are post-1974.