Is it the driver or the car doing the final braking in the video? Even if autopilot followed the wrong line it should perform emergency braking or evasive maneuver when the barrier is right in front of it. This is not just one error, it's two.
I assume the driver didn't want to wait and see if the car brakes at the very last moment, so it's hard to determine if the car would brake in this case.
This is the driver braking, you can hear the AP disengagement tone as the driver presses the brake pedal, and there is a distinct lack of AEB alert which should sound like this: https://youtu.be/FCegUNtgfuo