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.
Lady Parts - S2-E4
Continuity mistake: Chloe has a bruise on her left eyebrow and a cut on her right after the fight in the bar, but when she grabs Lucifer's phone the cut and bruise have swapped sides on her face, and then when she storms off they go back to their original sides. (00:30:48 - 00:31:30)
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.
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)
Lady Parts - S2-E4
Continuity mistake: In the tiki bar, when Chloe says she's LAPD, Maze chokes on her drink and her bottle is by her shoulder. When the shot changes to a close-up of Maze, the bottle is now up by her mouth. (00:17:30)
Liar, Liar, Slutty Dress on Fire - S2-E2
Continuity mistake: When Lucifer gets the doll out of the box, the doll's box is either face up or face down depending on the shot. (00:24:30)
Liar, Liar, Slutty Dress on Fire - S2-E2
Continuity mistake: When Lucifer is examining the doll, the way he holds it changes between shots. In one shot, he is holding the packaging, and in others, he's holding the item. (00:24:20)
Everything's Coming Up Lucifer - S2-E1
Continuity mistake: When Chloe goes to ask Ella if she believes in God, Ella has her hands on or off the microscope depending on the shot. (00:32:20)
Everything's Coming Up Lucifer - S2-E1
Continuity mistake: When Lucifer walks out of the police station having worked out who Bobby B is, Chloe has nothing in her hands in one shot, and a piece of paper in the next. (00:30:40)
Everything's Coming Up Lucifer - S2-E1
Continuity mistake: When Lucifer and Ella are talking for the first time, Ella's hair changes from neat to messy between shots and back again. (00:08:50)
Continuity mistake: When Lucifer hands Decker the blue cup at the party, the way she holds it changes between shots.
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)
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 ★