Triumvirate of Terror! - S3-E8
Continuity mistake: When Joker zaps Wonder Woman and her mother, they are both standing in front of their thrones and fall forwards. But when Wonder Woman stands back up, her mother, still unconscious, is suddenly off to the side and behind the thrones. (00:11:35)
Other mistake: In one shot after the droid fight in Gha Nachkt's ship, at one point when you see R3-S6 (Goldie), his eye is reversed. (00:12:42)
The Darkest Hour: Part Two - S4-E2
Revealing mistake: At the very beginning of the episode, as the knights are about to send Merlin to Camelot with Lancelot, the knights walk towards the camera. As they do, there's a patch of green screen the special effects department must have forgotten to remove between Sir Elyan and Sir Percival. (00:02:10)