In December 2017 we were involved in a rear end collision so violent the spare tire was knocked out from under the vehicle. Our vehicle, 2014 Buick Enclave VIN [XXX] was struck in the rear. The lap belt held us secure, but the shoulder belt allowed us to be tossed forward. My head hit the left windshield/top post leaving me looking like a racoon the next day. General Motors representatives, [XXX] CEO at the time ,stated the seat belts functioned properly. I injured my left wrist as a result of being thrown forward and have pain in it ever since then. We now drive a 2018 Buick Enclave VIN [XXX] that we purchased as a result of the December 2017 accident. We have noticed the same problem with the shoulder belts not working in sync with the lap belt, especially during a panic braking. Could this be product failure or just coincidence? I BELEIVE THIS WARRANTS EVALUATION! Thank you. My email address is [XXX] , mailing address is [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)