Other mistake: When Sportacus jumps out of his blimp, his crystal is missing.
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.