(at around 34 mins) Azura is wearing the blue necklace which Laverna after the characters have already discussed her not having it. In the next shots, it is missing again.
While Laverna is explaining her plan on the chalkboard, only Ruby, Topaz and a green fairy are in the room; she turns away and when it cuts back, all, except Azula, are there.
Approximately 59 minutes in (12 minute before ending): The light power being pulled from the purple (Amethyst?) guardian shows over top Ruby, and vise versa of Ruby's power over the purple guardian. Before and after, however, the display of these power beams are correct.