There Were Giants in the Earth - S1-E5
Revealing mistake: The Robot's lights wink out for a few seconds as it disables the force field.
Lost in Space (1965)
1 revealing mistake in There Were Giants in the Earth
Starring: Guy Williams, June Lockhart, Mark Goddard, Marta Kristen
Other mistake: When Don and Dr Smith are stealing Sesmar's control unit, look closely at the base of the electronic arch - Raddion is hidden from sight but the careful eye will see his golden feet.
Dr. Smith: Oh, the pain, the pain.
The Great Vegetable Rebellion - S3-E23
Trivia: Due to their uncontrollable laughter during filming of the infamous "Vegetable Rebellion" episode, Guy Williams and June Lockhart were written out of the next two episodes.