2019 GMC Acadia AWD Denali with just under 50k miles on it. Was going down the highway at about 60mph with adaptive cruise enabled. When attempting a quick acceleration the engine rpm ramped up and the transmission downshifted. About 5-7 seconds later the car lunched forward, while a bit sluggish is expected. After reaching about 70mph, the foot was removed from the gas and the vehicle continued to accelerate. The brake was pressed which disengaged the cruise after releasing the brake (without cruise enabled or pressing the gas) the car rev'd up to 6500rpm and launched forward abruptly. Heavy braking was done to contain the speed and get off the highway. On the exit ramp with the brakes locked as hard as could be the vehicle dropped to under 20mph with rpm's still over 6k. Shifted the vehicle to neutral (rpm's dropped to about 4k steady) and powered off to finish coming to a stop. The brake pads were smoking pretty bad, after looking over the vehicle nothing else looked out of the ordinary. Started the car a few minutes later and it drove normal for another 300mi. First time experiencing this issue but its definitely in the category of should never happen.