When Sheriff Alex Romero slams the objecting drug dealer's (cutter, packager, smuggler, etc) head into the glass bar it shatters/cracks - in the next take the glass of the bar is untouched.
Norman iMessages Emma in the cafeteria. If he sent the message it should come up blue and on the right hand side, but it pops up white on the left hand side.
Missing Foley. Near the start of the episode when Norma and Norman are walking down the concrete steps in front of the house you can clearly hear that the steps are actually made of plywood.