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.
Revealing mistake: Julia is throwing the tennis ball at the wall and is turning around to talk to Barbie. The military truck on her right has its front drivers tire on the line where the wall is supposed to be. This would mean that the whole front of the truck would be inside the dome. (00:07:44)