I have a feature with the music and adr in my itunes library (aiffs) on an external FW drive. Occasionally I get some weird things with these tracks once they are cut into a timeline and that timeline is rendered and mixed down. What happens is that the rendered version of a song or adr is out of sync, but if I dump the render files and re-render, the pieces return to their original sync. It's like it renders it incorrectly the first time. Could this be because I'm importing the items into my project from the itunes folders which live on a FW drive?