Revealing mistake: When Alvin and his mule get struck by lightning, if you look closely you can see the hair flip up on the mule's flank as he's hit with a whip to make him get up, and you can see the whip drag off to the side of the screen.
Sergeant York (1941)
1 revealing mistake - chronological order
Directed by: Howard Hawks
Starring: Gary Cooper, Walter Brennan, Joan Leslie, George Tobias
Revealing mistake: When Alvin and his mule get struck by lightning, if you look closely you can see the hair flip up on the mule's flank as he's hit with a whip to make him get up, and you can see the whip drag off to the side of the screen.
Alvin: Therefore, render unto Caesar the things that are Caesar's, and unto God the things that are God's.