Continuity mistake: Lucifer says that Amenadiel has a crazy theory that explains a whole list of things, but then doesn't say what the theory is. Pierce says "And you believe that?" as though it made perfect sense. But there's at least half a sentence missing. (00:02:50)
High School Poppycock - S3-E15
Continuity mistake: Lucifer is going through the blue 'Class of 3001' book, then puts down the green 'Class of 3001' book without ever lifting it up. (00:11:50)
Quintessential Deckerstar - S3-E23
Continuity mistake: When Espinosa opens the waffle maker, initially he's holding it facing up, slightly away from him, then the shot cuts and he's holding it close to his body, facing outwards. (00:21:20)
The Sin Bin - S3-E10
Continuity mistake: The eyes Lucifer draws on The Sinnerman change at various times. Even later, when he darkens them out, they change as well.
What Would Lucifer Do? - S3-E4
Continuity mistake: Pierce starts to put his phone away, then the shot cuts to him still on it. He then actually puts it away and then again it is in his hands, and he puts it away again. (00:31:28)
Continuity mistake: When Charlotte is in Linda's office getting therapy, Linda is shown drawing in her notebook next to a written description of Charlotte talking to a co-worker with bad breath, before Charlotte actually tells Linda the event. (00:16:50)
The Sin Bin - S3-E10
Continuity mistake: When Chloe and Lucifer approach Maggie's car, it's parked next to a car that has pulled in forward (so the trunk is seen). But after they open the door, the car next to Maggie's car is now pulled in backwards (so the front is seen).
Continuity mistake: The first half of the episode is based around the same time as early season 1, yet Reece is in the new precinct, which wasn't introduced until late season 2. (00:07:06)
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 ★