Infinite, I would figure that since you know all things car, you would know exactly how to fix this problem.

Chances are that since this problem is being exhibited above 50mph, it has something to do with the front wheel speed sensors as the speed of the vehicle is determined by the rears up to 50mph or if they are spinning faster than the fronts after a certain threshold is broken, ie, doing a burnout. After 50mph, the speed is taken from the front tires. Check out the wheel speed sensors or have a tech connect to it with the starscan and DRB3 to see if there are any fault codes. It may be intermittent enough that you're not seeing the BAS errors which will cause wing deployment but that your cruise will not function as it thinks there is an issue with differing speeds between the front and rear wheels.