Odd that this should end up in the moan zone?
Ultimately in an integer engine like PT you wouldnt clip the group inputs without obvious distortion.
In a floating point mixer internally you cannot supposedly damage audio intergrity unless you clip the output busses, the busses to the outside world ADDA or External Mix DSP Device, TotalMix Cuemix etc which are interger mixers again.
There are no warnings that you are "clipping" the group inputs its easy to clip the inputs if you sum many channels to the group.
And...Sonar handles it PERFECTLY...
However it COULD be because Nuendo-base creates rounding errors in the fader representation like -5 is actually -5.00001db so you dont get perfect cancellation, however my tests demostrate that its possible something a little more sinister like a truncation or rounding of the actually audio itself may be at work.
More testing needs to be done, because as usual the SB folks are more interested in a smoke screen than a real discussion.