This from Brian at Bricasti:
You can write that we are aware of it and are looking into it. it's a hard
thing to track down though, so it will take some time to find it and correct
it but we are trying to find it now. meanwhile if it occurs you can go in
and out of standby, this resets the DACs. Of course anything you can bring
to us on the events leading up to it would be helpful, and it will be easy
to update the MDx with the upgrade flash chip we used in the past.
You can write that we are aware of it and are looking into it. it's a hard
thing to track down though, so it will take some time to find it and correct
it but we are trying to find it now. meanwhile if it occurs you can go in
and out of standby, this resets the DACs. Of course anything you can bring
to us on the events leading up to it would be helpful, and it will be easy
to update the MDx with the upgrade flash chip we used in the past.