I just completed 600+ miles over the weekend. To say this issue is annoying is an understatement, especially as someone that gets motion sickness as a passenger. I sure hope it isn't induced on purpose to 'feel' if your hand is on the wheel.
As mentioned earlier, it seems to happen more regularly if autosteer is initiated when not centered in the lane, or when the m3 decides you should be centered differently. In my case, the car wants to hug the left line far more than I do, so the gentle swaying starts right away.
The only other clue as to what might be going on - the lines visualized on my screen are constantly 'dancing', getting wider and narrower, even on perfectly straight sections of well-marked roads. Perhaps the autosteer system is trying to stay centered in what it sees as wickedly inconsistent lanes?