I was hoping someone could have answered this, I'm having the same problem. Exporting as a mixdown works fine, but trying to burn a CD through Studio One 3 project it gets to the last song and cuts off at 27 seconds in, even though it is a 5 minute song. I had an old LG CD-burner that I thought was the culprit, but I just bought a new LG CD-DVD burner and it's doing the exact same thing, so it has to be something with Studio One 3 project.