Revealing mistake: In an overhead view of Oliver Hardy going down the sawdust chute, you can see it is a stunt double.
Busy Bodies (1933)
1 revealing mistake - chronological order
Continuity mistake: When Oliver has his hands trapped in the window frame, Stan looks at the blueprint of the Boulder Dam and the strap on Oliver's overalls is up. In the next shot, the strap is down, and in the shot after that, the strap is up again.