Cruise Control problems of the 2016 Buick Regal

Car applied brakes suddenly and fully 4-5 times during 200 mile trip on I-5 for no apparent reason while adaptive cruise control was on at freeway speeds (65-70mph). It occurred randomly, while following other vehicles, including semi-trucks, which are not in same lane and/or are significant distance away. Did so without any driver input or application of brakes. Decreased speed was so sudden, it caused driver's seat belt to tense up. Fortunately, there were no vehicles directly behind mine or my car would have been rear-ended at freeway speeds, resulting in potential serious injury. I took car to dealer where it was purchased (royal moore auto center, hillsboro, oregon (503-648-1153) on 8/9/17 and left it for day. Their technicians ran codes and drove car, but could not duplicate problem. (invoice # bucs780125). I was referred to Buick (800-521-7300) and it referred me to gm senior advisor team. Was assigned service request #8-3144154519. I spoke to service representative "christi", who told me there was nothing they could do unless the service technicians could duplicate the problem. Her only suggestion was that I return to the dealer to see if they could do that. I told her since the problem did not occur all the time, but only some of the time, that made no sense. I asked to speak with someone at gm who might have technical knowledge about this dangerous problem. She said she could not refer me to anyone at gm for that purpose. I told her (and later a second senior advisory team member- who are independent contractors and not gm employees), that I had found websites that discussed other owners of gm vehicles equipped with the forward collision alert and braking system and adaptive cruise control, ie, automatic braking systems, experiencing similar problems- their vehicles braked at the wrong time for no apparent reason. Nhtsa needs to look into this ASAP.