Other mistake: Archie goes out to the outside front porch to paint it. At the end of every show, the house they show doesn't have an outside front porch.
The Strange Fate of Conrad Meyer Zulick - S3-E9
Other mistake: When Doc Donovan reads the wanted posters, the physical description of Heyes mentions dark brown hair and brown eyes, which fits Pete Duel. However, by this episode, Roger Davis had taken over the role. He has light brown hair and blue eyes.
Is Lupin Burning... ?! - S1-E1
Other mistake: The logo of the evil organization, Scorpion, contains just a little misspelling. It's missing the R. (00:02:50)