In the scene where the boys are talking to Tyler whom is standing in a trash can if you look at Guitar dude in the background, he has no sunglasses on. And in the next shot where Tyler introuduces Guitar dude, he has sunglasses on.
When Kelly gives the boys their number, the one with the 2 on it keeps on changing.
When the assistant is putting the number card on Logan, you can see one on Kendall behind him, when he shouldn't have had one yet.