Revealing mistake: When Sookie finds Dawn dead, in the close-up of Dawn's body, you can see the actress' pulse at the base of her neck. (00:50:55)
Revealing mistake: When Connor and Cameron are trying to save Derek Reese from the police truck, Cameron walks on the Jeep's hood to jump onto the police truck. During her walk, we can see that it isn't Cameron but a stunt double. She doesn't look like Cameron and is a bit taller. (00:33:05)
Revealing mistake: During the exchange between Hevy and Cutup regarding Echo's enjoyment of their dull posting, the left pauldron of Hevy's armour is positioned weirdly, clipping through his arm at the bottom. (00:01:34)
The Scorn of the Star Sapphire! - S3-E5
Revealing mistake: While in the fight with Major Disaster, the double yellow lines on the road are wrong. They are too thick and close together. (00:12:30)
Revealing mistake: In the scene where Mitchell first visits McNair's van, Mitchell's reflection is visible in the window on the left side of the screen during the shot where he first opens the van door. The vampire lore of the show informs the viewer many, many times that vampires (such as Mitchell) and ghosts cannot be seen in reflections, pictures, or videos (their image "cannot be captured"). The reflection can be seen for roughly 20 seconds. (00:23:20)
Revealing mistake: In practically all the episodes, where we see Darken Rahl wearing a sleeveless shirt, there are visible vaccination scars on his shoulders.
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)