mute button in fader flip

[HF]

I noticed yesterday that if I have a plug-in open and I'm in fader flip 
mode, the mute button does not work. The solo button does though. Of 
course if I flip back to the normal mode everything works just fine. Is 
the mute button being used for something else within the plug-in or is 
this just normal behavior?

I've only tried this on the digi003 and maybe it's just a specific thing 
for the unit.

HF