Visible crew/equipment: When Cody is saying to Mark "You know it's really good to see you're dating," a crew member steps into the shot on the right side of the screen. (00:08:45)
Character mistake: Mark walks into the house and is surprised to see Cody there, and remarks that he heard he was back. However, just before this, when Mark entered the house, Cody's van - which Mark had to walk by to enter the house - was visible through the open door, so that should have confirmed it for Mark before he saw Cody in person.
Visible crew/equipment: When Cody is handing Carol the cashier's check, a camera and a crew member's arm are briefly visible on the right side of the screen.
Answer: From what I've read, the kid in question was the original actor cast to play Mark and was intended be closer in age to Brendan. For whatever reason, they recast the role with Christopher Castile and didn't bother removing the original actor from the beginning of the opening credits. I guess they figured people would just assume the kid was one of Brendan's friends.
Phaneron ★