Just a heads up. Rolling back to Windows 7 fixed our problem. Drivers etc are the same, so I conclude that a recent Windows 10 update broke quad buffering in OpenGL. I could be wrong, but I'm confident enough to post that here.
Some supporting evidence:
https://answers.microsoft.com/en-us/...e-ecaa215d012a
http://www.datem.com/support-alert-w...sables-stereo/