I don't have this problem (I have Bilsteins! Hahahah... ok, just kidding) but I wonder if it has to do with the alignment...

My engineer father told me never to get a thrust-angle alignment (which aligns the front wheels to compensate for & balance out any misalignment of the rear axle) because it would leave the car with an inherent tension in the suspension. What you guys are describing sounds a bit like such a tension being released when your rubber hits the slippery spot. (I made that sound dirty, huh?)

Diagnostic question - If you drive straight over a series of expansion joints, does the VX always hop to the same side?

When's the last time you had an alignment check?