Two of you guys really helped! I watched the camera target and it was definitely drifting something fierce.Good test! I then checked out my navigator one more time ... and found the culprit. It was a very-well hidden new setting that came in a recent driver Space Navigator update.
These settings are not seen anywhere in the standard control panel; they are only available & visible when you set one of the buttons to trigger a 'pop-up menu' (set via from the control panel) and then press that button. You get a small pop-up menu with several options : you want to go the 'rotation center' and turn everything OFF and then click on 'hide' so you don't see the small blue cube every time you use the navigator. (It's supposed to help you know where the center is.)
Yes, someone thought a tiny blue cube in the middle of your screen would somehow help. All of these new rotation features are both well-hidden and bug-like. Thanks, 3D Connexion / Logitech.