Autopilot Incident in Slow Traffic

Occurred on January 13, 2020 / Milpitas, California, USA

Info from Licensor: "This happened on Jan 13 when driving on Autopilot in the Bay Area. As usual, I used autopilot for the heavy stop-and-go traffic, and I was following this car carrier truck for a few minutes. The average speed was around 10 miles per hour, and the AP distance was set to 3 cars.
I didn't expect such a thing, and before I noticed or could react, it ran into the car carrier semi. I have used AP for about 20k miles with no incidents. I'm wondering why it started moving when the car carrier truck in front of me was stopped. That' how all sensors (ie. cameras, radar, and sensors) suddenly ignored the giant semi. I have reported this to Tesla."