Revealing mistake: We can see Ecliptor's zipper from behind - slightly revealing on Saban's part, considering Ecliptor is supposed to be an evil monster henchman of Astromena's.
Crystal Blue Persuasion - S3-E15
Factual error: When Frank, Olga and he rest of the Back Step Team meet Commander (a Navy O-5 Rank) William Streck, he is dressed in a U.S. Air Force Uniform with the rank of Colonel (O-6).
The Planet of Dr. Moreau - S1-E4
Audio problem: At the very beginning of the episode, the Silver Surfer emerges from a wormhole screaming "No." If you look closely as he is approaching the camera, his mouth is closed until just before he slows his approach.