Who's da New King of Hell? - S4-E10
Continuity mistake: When Lucifer, as the Devil, tells the demons to go home, all the bodies fall down. We see the bodies fall down behind Chloe, too. After the shot of the Devil, the camera goes back to Chloe and the bodies all fall down again.
Expire Erect - S4-E5
Continuity mistake: Near the end, as Dan says "this is all on me", in a shot from behind her Maze is spinning her knife then stops, gripping it pointing downwards in her fist. Cut to a new angle and her hand is instantly turned over, with the knife sticking out sideways.
Answer: Boo Normal and Once Upon a Time were going to be part of season 4, then the show got cancelled (before being picked up elsewhere). As such they were added on to the end of season three as "bonus" episodes, hence the continuity being off. But not really a mistake, just a quirk of broadcasting. Boo Normal was originally going to be between the episodes "High School Poppycock" and "Infernal Guinea Pig" in season 3 before being slated for season 4, presumably because aside from the point you've raised, it was fairly flexible, continuity-wise.
Jon Sandys ★