Plug-In Stereo Image Issues (including Plus 10db plug-in)

I'm working on a new project and am having a bit of a problem.  It seems some plug-ins on a stereo bus are causing the stereo image to shift.  For instance, I am sending a mono vocal track into a stereo bus (only track sent to this stereo bus at this point) and using plug-ins on the stereo bus pro-channel.  I have the Plus 10 dB channel strip on the bus and when I use the dry knob (moving towards 100% dry), the stereo image moves to the left channel.  
 
Should note that when I engaged the 10db plug-in, the right channel on the stereo bus showed an increasing signal as I went from wet to dry and I heard a buzz only in the right channel as I did this.  This even happens when there is no playback.  I then deleted the bus and started over again.  The majority of the issues are still there (imbalance and noise in right channel only as I adjust the wet to dry setting; however, it no longer shows an increasing signal in the right channel;  Remember, the left channel actually increases in volume.).  I also am having a slight stereo imbalance issue with the Waves ADT plug-in, which I am currently demoing.
 
I have tried forcing the Plus 10dB plug-in to stereo operation from mono processing, and vice-versa (deleting then re-adding the bus in-between changes), but that didn't fix the issue. 
 
I have checked my panning settings, so that's not the issue.  Any thoughts?  Please let me know if you need any additional information.

Thanks,
 
 
Paul

Thanks. 
 
To clarify for others, I do have it in an FX bin on a stereo bus and am using the VST3 version.  I have no issue if I add it to the Pro Channel on the track, instead (again, in an FX bin).
 
p

Does VST2 format have the same problem?

Go to Preferences > Audio > Driver Settings and uncheck "64-bit Double Precision Engine" then open the project.

Not in this case. However, it should not be necessary to turn off the 64bit DPE to solve this problem.