Revealing mistake: When Ed and Dexter are in the ventilation shaft, watch when they fall in the trolley thing. If you look carefully you can see Ed's wig hanging on the edge. It's got a good burger hat on it.
Visible crew/equipment: In the end of the movie when Kurt is arrested, the camera and a crew member wearing sunglasses are reflected in the side of the police car.
Visible crew/equipment: When Dexter is driving with his friend in his mom's car you can see a police officer stopping traffic for the shoot, when they make a right turn on to the street where the car accident occurs.
Continuity mistake: As Mr. Bailey brings back a Mondo Burger, Spatch picks it up with a spatula. The close-up scene shows the spatula bending. As Spatch throws the spatula back down, the spatula is straight again as he grunts off.
Continuity mistake: When Dexter is having lunch, there are trays behind him. When Mr. Wheat is with him, the left trays are tall. When Ed comes, the left side is short.
Continuity mistake: In the beginning when a talking burger comes out of the bag, sauce packs in the tray at the bottom right change between shots.
Answer: We don't know that he doesn't. He could simply go to a different school where the school year ends slightly earlier. It's also possible that he's already graduated or dropped out.
LorgSkyegon