Factual error: When Tom has decided his scout group will have to go for the food and then his look for his son later, they are stood on a green. There is a war memorial dedicated to both World Wars, 1914 - 1918 and 1939 - 1945. That's got to be in Canada, as the USA didn't enter either war until later than those dates. (00:28:00)
Revealing mistake: The swords Jayden and Dekker use often bend when striking each other, revealing they are rubber blades and not metal.
Revealing mistake: When the students see themselves in the TV, (which meant that Skidmore was watching them because Chyna had given her a hidden camera) you can see in the TV that there is actually a green screen on the screen and the video is not actually playing, it was just edited in later.
Episode #1.4 - S1-E4
Other mistake: Dr Ambrose, talking about a doctor tending to patients on death row, says "Hippocrates is spinning in his grave." The subtitles say "Hypocrites is spinning in his grave."
Continuity mistake: Chris has a blue dye pack explode on him, covering the front of his clown costume and face. But then shortly after, the dye is gone from his face and clothes.
Continuity mistake: When Irina meets XIII on the river dock, she leaves her car, closes the driver side door and walks to XIII. Moments later, when XIII is shot, she runs back to her car, where the door is wide open.