My theory is that the 8GB Nano often has defective positions in its flash memory. Any song that is stored using one of these defective memory positions is simply truncated when the Nano plays the song to that point. The same song usually plays perfectly if the song storage sequence is changed during next sync. This will happen if new songs are added, existing songs are deleted, or the name of existing song(s) are changed. I am not sure if the other Nanos have this same defect or not.