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.
Continuity mistake: When Lucifer hands Decker the blue cup at the party, the way she holds it changes between shots.
Deceptive Little Parasite - S2-E15
Continuity mistake: When Chloe and Mazikeen are at the private school checking out the other parents, Chloe is alternately holding Mazikeen's hand and not holding it between shots.
The Good, the Bad, and the Crispy - S2-E18
Continuity mistake: When Lucifer is sending his mum to her new world, he is standing for the whole scene. They show a shot of Charlotte collapsed on the beach, and in the same shot, you see Lucifer on his knees in the sand. The very next shot, he is standing again. You only ever see him fallen on his knees when time starts back up again and the detectives realise where they are, which is a bit later. (00:37:25)
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: 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)
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.
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).
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)
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)
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)
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)
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.
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.
Is This Really How It's Going To End?! - S5-E15
Continuity mistake: When Dan hands Ella the phone number, he's holding it by pinching it on the bottom. In the next shot, he's holding it on the side.
A Chance At a Happy Ending - S5-E16
Continuity mistake: A guy with a face tattoo is in the opening scene, then the tattoo isn't there when the guard gets up.
Continuity mistake: When Maze says goodbye to Lucifer and takes off on her motorcycle, the cars around change. You can see 2 cars parked with a car next to it with its blinker on. Then there are 3 parked cars and the end one has its hatchback up. Then as she drives off, it's a van. In the next shot the van and hatchback are gone.
Continuity mistake: The squiggle that Lucifer draws over "Become God" on his checklist changes between shots.
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 ★