I'm driving an M3 on 16.2, but also had this happen on the last version.
Both times this happened, I was driving at about 50 mph on Autopilot, daytime, good lane and road conditions, when the car suddenly went left into a left turn lane. I always keep "pay attention and have hands on the wheel" thank goodness! This motion would have put me into a head-on with traffic both times.
Since this happened, I've watched closely, trying to determine what was different about the road configuration that caused the problem, since there are often left turn lanes on the roads I drive. I haven't figured out what caused it in these 2 situations.
I still use Autopilot, and really appreciate it, but I'm wary.
Have others experienced this? Should I have done a "bug report" or are motions take pull-out of Autopilot noted in some way by Tesla technicians?