This is hard to see. At the end, when Jody tells Cooper that he's a great choreographer, but a bad boyfriend, she runs her fingers through her hair. If you look closely you can see that a piece of hair from the right side of her part was flipped over to the left side. Then, when she sees Charlie, you can see her from behind running over to him, and the hair is still on the right side. It's considerably shorter than the rest of the hair. They then cut to a shot of her from the front, and her hair is perfect again. There is no way she could have moved it over, and it wouldn't have fallen because it stayed that way even when she was running.