When previewing a sound that uses a sample the sound browser is pretty much broken. It was confusing the hell out of me and I was at first thinking that I failed to save my one hour edit of “the perfect snare” to the +Drive.
The problem is that the sample slot number used when saving the sound from the track to the +Drive is the sample slot number used for previewing. So in a different project when previewing sounds you are very likely to either end up with a completely different sample playing or just silence if the sample slot is empty.