Continuity mistake: In the scene where Blu and Jamie talk after Blu's trip to G Major, Blu's bra straps keep switching from lying under the straps of her tank top to out, and then back to under the straps in between shots. There's no way they could have moved on their own because they are very tight against her shoulders.
Other mistake: In the scene where Jude is recording "Ultraviolet" in the studio, she sings, "I don't care if it burns my eyes," while the actual lyric in the song is "I don't care if it hurts my eyes." Having just performed this exact song at the beginning of the show, it's highly improbable that she would forget the lyrics.
Continuity mistake: In the scene where Spied and Karma are in their house, in one shot, Karma's dog walks across the couch and onto the end table. However, two shots later, the dog is back on the couch and facing the end table. Now even though the shots are not consecutive, there was still no time in the 3-second shot in between for the dog to have moved back to the couch.