Lucifer, Stay. Good Devil. - S1-E2
Continuity mistake: When Chloe asks Jimmy about Lucifer at the end of the episode, her good arm is down her side when seen from behind, or folded in the frontal views. (00:42:25)
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).
Stewardess Interruptus - S2-E11
Continuity mistake: When Chloe tells Lucifer that her main priority is the case and that nothing is going to happen between them, her hair on the right side of her face tucks itself behind her right ear between shots. It then falls down again, then tucks itself once more. (00:34:40)
Continuity mistake: In the scene in the warehouse, Chloe and Lucifer end up right below where Corazon is tied up. Then blood drips on her hand prompting her to look directly above her head. In the next shot Lucifer turns around and suddenly they're both meters away, looking at the contraption from a distance. (00:26:50)
Continuity mistake: When Lucifer helps Amenadiel, who has been stabbed with one of Mazikeen's daggers, Lucifer has one hand on Amenadiel and one by the dagger. The camera cuts, and now he has both hands on Amenadiel. (00:21:45)
Continuity mistake: When Linda asks Amenadiel if he is a real doctor, he has both hands raised. Camera cuts and now he only has one raised. (00:08:20)
St. Lucifer - S1-E11
Continuity mistake: The way Malcolm holds the gun when showing it to Dan changes between shots. Note his grip. (00:06:30)
St. Lucifer - S1-E11
Continuity mistake: Just after saying the widow could hold the charity event at Lux, Lucifer has his hands clasped. As the camera changes angle changes however his hands are apart. (00:07:30)
A Priest Walks Into a Bar - S1-E9
Continuity mistake: At the end on the balcony Lucifer's cigarette switches hands between some instant cuts. (00:36:30)
A Priest Walks Into a Bar - S1-E9
Continuity mistake: The position of the priest after he has died changes between when Lucifer walks over to the other person and when Connor walks over to the priest. (00:35:00)
A Priest Walks Into a Bar - S1-E9
Continuity mistake: When Lucifer goes to speak to the priest on the balcony after finding out about Connor Lucifer has his right arm by his side as he walks out. When the shot changes to outside his right arm is bent at the elbow and in front of him. (00:28:30)
A Priest Walks Into a Bar - S1-E9
Continuity mistake: When talking to the priest in Lux, Lucifer's hands are constantly changing positions between cuts. (00:24:20)
Continuity mistake: When Malcolm lifts his jacket to show he is unarmed his jacket position changes between the two shots. In the first shot his jacket is hanging low and in the second it's held high. (00:19:40)
Favorite Son - S1-E6
Continuity mistake: The way Trixie grabs the chocolate cake differs from raising her hand up to Dan and just holding it out in another shot. (00:37:20)
Favorite Son - S1-E6
Continuity mistake: When Dan hands Trixie the chocolate cake, he holds it with 1 hand then two depending on the camera angles. (00:37:20)
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 ★