I'm running 9c+ and I got into a mode while listening where it would continue to advance but there was a stuttering every 0.75 seconds (seemingly). Skipping to the next song or repeating the prior one didn't make the problem go away. I didn't try stopping and starting, I made the mistake of resetting by pulling the device out of the dock and putting it back (and everything returned to normal).

All my music is ripped with MusicMatch @ 80% VBR (~160Kbits/sec). This causes confusion with the time-remaining calculation as well as causing the drive to keep spinning 90% of the time instead of 25% of the time.