Audio problem: A very audible echo is heard when Jon-boy says "I'm trying to work up there".
Visible crew/equipment: Near the end, when John-Boy thinks he may know where AJ has gone he gets into the vehicle with Martin Walters, then as Todd starts driving away the reflection of a reflector screen becomes visible on the rear window, and it looks like the reflection of the boom operator's raised arm is visible as well. (00:46:40)
Revealing mistake: When John Boy and the others are watching the movie being shot, a helicopter can be heard. This takes place in 1936 with The Abdication of Edward VIII, and there would be no helicopters around at that time. (00:25:20)