Mr. Garrity and the Graves - S5-E32
Deliberate mistake: Garrity blackmails the town citizens into paying him not to resurrect their unlamented "loved ones." Amazingly, every man in the saloon just happens to have hundreds of dollars ($500 - $1200 each) in his pocket to pay up with. In 1890 money, that's roughly equivalent to a group of modern-day bar patrons all carrying ten to thirty thousand dollars around in their pockets. The scenario was apparently used in spite of its incredibility just to more quickly advance the plot.
Deliberate mistake: The signs at Dachau Concentration Camp are in English.
Deliberate mistake: Sport's voice is noticeably dubbed by a different actor in several scenes throughout the episode. Her voice inside Aunt T's house is the original audio track done by the child actor. During the other scenes, the voice is done by June Foray (uncredited).
Deliberate mistake: The first of two twists meant to come at the end of this episode was the revelation that the mysterious dark rider chasing Anne was herself - 25 years in the future. According to writer Richard Matheson, the director chose, for some bizarre reason, to deliberately spoil this "reveal" by inserting a close-up of the rider early on, showing the viewers who she was at the outset.
Deliberate mistake: The woman being attacked by the tiny astronauts lives in very primitive conditions, suggesting a hard life with no electricity or running water. But close-ups of her hands show she has perfectly manicured nails.
