Revealing mistake: In the scene where Norman visits Caleb at the motel on his own, after hearing Norma and Dylan argue, he gets into an argument with Caleb. Norman then pulls a knife out high above his head, at which point you see it is a prop/rubber type knife. The handle aimed at Caleb but the force Freddie Highmore has used to pull the knife up and back causes the blade to bend and aim toward the ceiling.
Bates Motel (2013)
1 revealing mistake in Check-Out - chronological order
Starring: Vera Farmiga, Freddie Highmore, Max Thieriot, Olivia Cooke, Nicola Peltz
Continuity mistake: Norma reaches over to touch Chick's walking stick with her right hand, but the next shot shows her using her left hand.
Dylan Massett: You'll do anything to get your way.
Norma Louise Bates: I've never gotten my way, and that includes being your mother.