I've only had mine for a couple of days, but I did have an occurrence:
I was going from a high res, 96/24 file, to a redbook file. The redbook file started playing at high speed. I rebooted the DX100, and then the redbook file played normally. I have not been able to duplicate this, I chalked it up to a freq occurrence.
For my case, I don't reboot rather I just pause, then just open the SRC option and select a different SR then go back to native play.