Audio problem: When Lizzie is performing at the end of the movie at the awards show, at the part where we see her from the back facing the blue light, her voice sounds like it's changing. It seems like it's someone much older singing, or the synthesizer went wrong. It just obviously isn't Lizzie's voice anymore.
Audio problem: At the end of the movie when Lizzie is singing, her lips don't sync with the music.
Answer: No one knows for sure, but he likely lost his career and faced a lot of lifelong humiliation as have previously singers who were found to be secretly lip syncing to someone else's voice.