Deliberate mistake: When White almost fights with Exley in the street and is pulled away, the public mailbox by the side of the road is all blue. Mailboxes back then were red on top and blue on the bottom.
Deliberate mistake: When Barbara Wilson/Batgirl first arrives she is standing on a ledge beside the front door when Robin answers the door. She then exclaims, "Oh. Uncle Alfred." However she could not possibly have seen him, not just because of her angle, but also the fact it is after that statement that he first comes into view. (00:34:10)
Deliberate mistake: When they fight in the hangar and Troy is thrown back by the jet engine, his face and other parts of his body should have been burnt quite heavily. Such a jet engine has temperatures higher than 450°C about 5 meters away, and Troy is even closer than that.
Deliberate mistake: As Roper drives the Dodge into the shipyard watch the underside - no sign of McCall, even though he's visible under the body when he comes out of hiding.
Deliberate mistake: Declan and Preston are hanging out at an airfield in a blue car when they realise one of the numbers in the notebook they have is an FBI access code that The Jackal now has. In establishing shot of this scene you see the blue car sitting more towards the left with Declan on the hood. Then when Preston calls in this finding and they get a helicopter to come pick them up, in the shot with the chopper coming the car is now suddenly much further to the right. It seems they had to move it during filming to allow a place for the chopper to land. (01:19:05 - 01:20:30)