Revealing mistake: Billy, a young village boy, wants to join the army and fight in the war, but he is under the 18 y/o age requirement. He's supposed to be about 15 or 16 years old, but it's quite obvious that the actor playing him is in his early 20s and definitely looks old enough to join.
Eye of the Needle (1981)
1 revealing mistake - chronological order
Directed by: Richard Marquand
Starring: Donald Sutherland, Kate Nelligan, Stephen MacKenna, Philip Martin Brown
Visible crew/equipment: After Faber has hitched a ride (when his motorcycle failed,) the driver pulls over to let him out. As the car pulls away from Faber you can see a crew member in a blue vest type coat reflected in the passing car window.