Character mistake: The party is supposed to be "One of the premiere social events of the season", but the only people invited (Higgins knows for sure who is gonna come, so it's not like there's low attendance because of the weather) are a Prince from a fictional European state nobody knows about with his commoner wife, the editor of a poetry magazine that needs Robin's funds to survive, a sports star and Robin's accountant. 5 people in total, already all in Robin's pocket, and nobody else in attendance. While you could say that having royalty and a golden glove winner is certainly noteworthy, those people don't meet anyone else. Hardly a 'social event'. (00:04:00)
Break Out the Pampers: Part 2 - S3-E2
Character mistake: Near the end of the episode, when Ms. Rafkin stops by to see the Rush family, Sara greets her by name. Ms. Rafkin (who thinks her looks have changed due to a facelift) asks Sara how she knew it was her. Henry told her by her voice which she accepted as the answer. This wouldn't be a possibility since Sara said hello before Ms. Rafkin spoke.
Episode #1.1 - S1-E1
Character mistake: In the opening minutes of the first episode, as the Erasmus is struggling through a storm, Blackthorne is told that the boatswain is dead. He checks the corpse and then says, "Get the body aloft," which would entail carrying the deceased up the mast. The correct order would be "Get the body topside."