I am working on a video around 20 minutes long. Basically what's going on is a cop is chasing another car. The car being chased is blaring "Back in Black" by Ac/Dc. Since the music is coming from only one car, I have to raise and lower the decibel level of the music depending on which car the camera is in/by. When I play back the scene, on one of the clips the music track changes volume on its own. Nothing changes in the Timeline. Any ideas on what might be causing this?