Other mistake: When Derek is tortured by Kate and turns into his wolf form his eyes don't glow.
Other mistake: When we see young Peter Hale convince young Derek to turn Paige with Ennis' help, it is said that Derek is 15 when he killed Paige. And according to Wikipedia Derek was 16 and in school during the Hale house fire. Although when Derek is 15 we see Peter Hale played by a younger actor but during the Hale house fire Peter is played by Ian Bohen. How did Peter change so much in a year? Ian looks much older than the actor who plays 15 year old Derek than the actor who plays young Peter does.
