Hi Cakewalk Community.
 
Following problem here:
 
In order to save some CPU I have bounced a Drum Buss to a track and then routed the track back to my master fader, just like the original Buss was routed. In order to check if my Bounced Buss really sounds exactly the same I have then soloed the Drum Buss and my new Bounced Buss and flipped the phase on the latter.
No changes were made, no reverb sends, no faders have been moved etc.
 
And here is the thing: They don't null as they should do.
 
Am I missing something here or is it really Sonar's Engine that is the culprit?

Often when this is reported its due to a routing issue. Something is not going where it is supposed to go. Make sure all tracks that are meant to go to a particular buss actually do.  

Thanks for the fast answer John,
 
I checked it and all the Routing was correct. I have since found the flaw: Iwas using a Plugin called Aquamarine ) Shadow hills compresser emulation) on my Drum Buss and it seemed that this has been messing with the phase. This plugin has been updated a week ago and I have installed the new Version today and it is all good.
 
Thanks! :)

Wow, I am so glad you found the answer. I was going to suggest that it had to be your Shadow hills compressor emulation but I was sure you had already checked that.