The "bug" is that MANY MANY .mp3 encoders fail to fill in the "timestamp" information correctly when creating .mp3 files. As a result, various players (including the Empeg/Rio) may screw up when trying to fastforward or rewind within a song, or even just display the wrong Elapsed time for a track.

If the FF/REW buttons fail to work on a particular track on your Empeg, then you know that track has VBR timestamp problems.