As Road Turtle says in his post, I have experienced these same characteristics of the adaptive cruise on my 2018 F150 and my 2021 F350. I have manipulated the distances but the adaptive cruise acts similar regardless of settings. The F350 KR I test drove before ordering my 2021 F350 seemed to respond quite differently. Not near as much abrupt braking and accelerating. I ordered adaptive cruise on my new truck which I regret now as I run it in the Normal Cruise mode all the time.