The Elements of Harmony (2) - S1-E2
Other mistake: At the end of the episode when Princess Celestia is talking to Twilight Sparkle you can see that Princess Celestia's tail is on top of her leg instead of in-between. It's covering her cutie mark.
My Little Pony: Friendship Is Magic (2010)
Episode list - season 4
Starring: Tara Strong, Tabitha St. Germain, Ashleigh Ball, Andrea Libman
More mistakes in My Little Pony: Friendship Is Magic
Discord: 'What fun is there in making sense?"
Trivia: Pinkie Pie didn't use the trombone to get rid of the parasites. That means she planned for the exact ending. Not unlikely, considering Pinky Sense.
Question: During the song, 2 cute bats are seen with 'Jude'. When the cute bat couple is shown again, Jude is nowhere to be seen. The couple doesn't look at all concerned. When Applejack was singing "These creatures have a one-track mind!", Fluttershy appeared without Jude and couldn't take him or her home and then come back in about 5 seconds. So, where did Jude go?
Answer: He wasn't there in the first place. It was probably someone else.