During the movie take a look at Megan Fox's fingers. Throughout the movie, her fingernails are shown to have chipped nail polish. But for at least one scene when the camera flashes to her hand, she has no fingernail polish. I believe this scene occurs when they are at the Dam where Megatron was kept. After this scene, when the camera flashes to her hands again, she has the chipped fingernail polish on her nails.