Mixdown (Bounced tracks) stereo tracks are different level

I don't know when this started as I haven't done any mixdowns for the last couple of months. 
However, today I've done two mixdowns (bounce to tracks) and the stereo Left track is lower volume level (approx. 3DB)  than the right track.  They both should be the same (I'm bouncing mono tracks).  I didn't notice this on mixes I've done (since I got Sonar 6) and I'm doing it exactly the same way (using defaults in the Bounce function). 
 
I'm using the latest Sonar Platinum version (2017.01).  I rolled back to the previous version and did a mixdown and the same thing.
 
My recording interface units are not the problem (the mixdown should be strictly a Sonar function).  Just in case it was, I used my backup unit and it did the same thing.  My primary is a MOTU 896mk3 Hybrid and my backup is a Focusrite 6i6 2nd generation.
 
I had marked this solved but the problem showed up again today. 

I can see it, looking at the waveforms in Sonar and in Goldwave.  I can also see the difference in the level meters for both channels. 
 
I got around it, for these two mixes since they are all mono tracks, by mixing down as mono instead of stereo and then converting to stereo in the track.  Both left and right are identical that way.

Bouncing to tracks will generate a +3db bump if you use the default pan law. I ran into this and changed to another pan law to correct it. 

If you read the help files it states that the default pan law "0" (center) will add 3db to anything that's panned hard left or right when you bounce to tracks. I think Sonar is seeing your mono track as a hard panned stereo track when it's bounced to a stereo track. Try the pan law at the bottom of the drop down list in preferences, I think it might fix your problem.

Rolled back to 2016.09.  Did a mixdown with one of the projects that mixes with the left channel lower than the right and NO PROBLEM - both channels are the same level.  Using the same defaults in Bounce to Track(s).
 
I guess I'll have to start from the 2016.09 and try each monthly upgrade to see where it goes off.
 

The imperfect world of technology

I don't think mine was exactly the same.   When Sonar created the "stereo" track from mono tracks on mixdown is where I encountered the different levels for the Left and Right tracks.  BUT, If I mixed down the project tracks to a mono track and then created the stereo track from that mono track both Left/Right levels were the same.  This suggests Sonar has different utilities for creating stereo tracks.  Fortunately one of the older versions corrected what was wrong with my 2017.01 version. 

Anyone? 
From other comments it looks like trying to contact Cakewalk support is fruitless, so I need input here.
 
Thanks/Jack

They are set at "0".  I use the console view as the meters allow seeing the difference in channels.  It would not appear to be hardware (recording interface units) as it does the same with either my MOTU or Focusrite unit connected.
 
I exported the mix as a wav and then opened it in Goldwave so I could get the exact measurements.  The difference in the left/right channels are not enough to be heard but concern me as they should be exactly the same considering I'm mixing down mono tracks to a stereo track.
 
This time I rolled back to an earlier version 2016.10 and it didn't "fix" it like it did before (maybe I need to roll back further). 
 
The utility that converts to stereo in the Bounce to Track(s) mixdown function does not create the same level stereo tracks.  If I knew where that was possibly I could replace that with the same function in my other Win 10/Sonar configuration as it doesn't have the problem.  Or something in the Bounce to Track(s) is where the problem is and not the stereo conversion as I can mixdown to a mono track and then convert the mono track to stereo and its OK - both tracks are the same.  I use defaults in the Bounce to Track(s).
 
A Complete uninstall of Sonar is out of the question as I would probably lose some older VST's.  The install I have was "upgrade" from X3 (and X3 is still installed).

IS it a bug, or the unintended consequence of continuous development?

The older Sonar version levels have changed since rebooting the PC.  I uninstalled Sonar, using the CCC, rebooted the PC and then installed the current version.  There is still about 0.75 db difference in the channels.  Realistically not much but there should not be any difference - both channels should be exactly the same.  If I mixdown to a mono track and then convert to stereo both left and right levels are exactly the same.  This would point to the Bounce to Track(s) stereo conversion as the issue (I'm using the defaults in the Bounce function).
 
I tried this with Studio One 3.  I have a version I got with a Presonus hardware purchase but don't really use.  I exported each mono track from Sonar and imported those tracks into Studio One 3 and then did a mixdown and both stereo channels are the exact same level (what is expected).   
 
FWIW I can't say this is a new problem. It may have been there all along and I never noticed it before.