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)
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)
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 ★