PT 001/Mackie HDR sync ossillation issue

[where02190]

HDR Pro, G-4 dual 1ghz with PT 001PTle 5.2.1 software. HDR is master, wordclock from HDR connected to spdif in of 001. HDR sends MMC and MTC to 001.

Occaisionally in the past day or so, when I jump around within a project starting and stoping rapidly, Protools will output a rather laoud oscillating tone, that can only be stopped by closing the session. Subsequently PT will not run again sync'd w/o quitting and restarting PT.

I've not made any changes to the settings or set-up, and it has been performing flawlessly up til now. I've not really done this fast shuffing around before that much, and think it is the issue, that perhaps the fast change in clocking time and commands locks the 001 up and thus the ossillating tone.

Anyone else experiencing this, or have any suggestions, other than slowing down my rapid fire comands to the HDR?

Thanks-Nick

[where02190]

bump.