Wolf's Bane - S1-E9
Revealing mistake: When Jackson asks to "Inquiry-It!" on Melissa McCall's work computer at the hospital, the search engine is fake due to the search bar, making it clear it's a local file, not online: file://Users/jamesonfilm/Desktop/htm/newsearch.html. (00:09:14)
Visible crew/equipment: After the Alpha wolf breaks through the movie rental window, it frightens Lydia, who was parked outside. As the camera pans closer to her face, a protective plastic cover hanging off the camera can be seen in the car window's reflection. (00:03:55)
Continuity mistake: When Scott runs into his room after the party the shadow of the blinds can be seen all the way across the room, but in the next shot of the window, the blinds are only halfway down. The shadows cast doesn't match.
Other mistake: When Derek is tortured by Kate and turns into his wolf form his eyes don't glow.
Continuity mistake: When Derek finds the note on his car it's snowing, in the next shot it's not.
Character mistake: The poster advertising the Formal misspells Beacon Hills as 'Becon Hills'.
Second Chance at First Line - S1-E2
Continuity mistake: When Allison opens her locker, the things inside change from shot to shot.
Continuity mistake: When Scott loses his asthma inhaler, we see it fly out of his hand and land on the ground and it is a light khaki colour. Later on, when Scott and Stiles go back to the woods in the day to look for the inhaler, they come across Derek and when Derek throws Scott his inhaler, it is a white colour.