Burst Mode problem ?
Well, I'm wrong. Sort of. It seems the VR + Burst Mode "problem" really is a function of camera speed.
I put the ISO at 1000, and at 1/1000th in Burst with VR on / VR off makes little, if any, difference. I stand corrected. But at lower speeds and/or lower ISO the issue comes back but uniformly.
So it isn't the lens, it isn't the camera, it's the light... plus operator error.