There have been other similar cases lately, which clearly indicate problems with the car.
The driver has put up the footage from all the cameras of the car, so he has done what he can to provide evidence.
https://www.reddit.com/r/TeslaFSD/comments/1ksa79y/1328_fsd_accident/
It's very clear from the comments, that some have personally experienced similar things, and others have seen reporting of it.
This is not an isolated incident. It's just has better footage than most.