Any mistakes can be allowed because it is very unlikely that all the scenes appeared in chronological order, and they were filmed at 2 different concerts
During most of the concert footage Miley/Hannah is wearing a watch that appears and disappears on and off during the movie.
Miley is given flowers by a person in the audience. She places them on the stage in front of her. In the next shot they have disappeared.
During one song, Hannah is wearing a denim vest. The vest disappears and reappears from different camera angles, probably because the movie was filmed over two separate concerts.
During the Jonas Brothers song the number of reserve guitar picks that are in the mike stand change from two to four, and back again several times.