Your Time Is Gonna Come - S4-E1
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.
Possession - S4-E9
Continuity mistake: In the scene where Jamie and Zeppelin are folding laundry, Jamie hands Zeppelin a pair of pants and in the next shot, the pants are back in Jamie's hands again.
Jude Harrison: Meatless meatloaf?.. Isn't that just loaf?
Trivia: In season 2, episode 2, Jude dyes her red hair blonde. In actual fact, Alexz Johnson, who plays Jude, is naturally blonde.