Based on that NTSB description, veteran users of AP will understand exactly what happened:
1. Model X was following a lead car.
2. That lead car was in the "non-travel lane", finally realized their mistake, and moved over at 7 seconds prior to the crash. That's why the steering begin to shift left--it was trying to follow the lead car, but saw the lane markings and then stopped following the lead car.
3. Model X then sped up to driver's set speed as it wasn't following a lead car anymore.
4. When a lead car changes lanes, AP can take a little extra time for the radar to lock on a new target (and stationary targets will be disregarded). That's a time where the driver needs to be paying extra-close attention. Same issue with the firetruck. AP following a car, car changes lanes, AP car runs into firetruck.
Recommendations:
1. Driver must stay engaged.
2. Tesla should work on rapid acquisition of stationary objects in radar's path of travel.
3. CalTran needs to update their road markings and improve signage/safety in that area.
Note that this scenario (lead car changes lanes to reveal a hazard) is explicitly covered in the manual. While Tesla should work on it, I wouldn't be too concerned about restrictive action. He who follows not the manual may experience negative results.
Case closed.
This is the second time I've closed an NTSB Autopilot investigation early for them. I think they need to start paying me.