From what I got during the time I had available to listen, there were two problems: 1) Driver started the turn when it was possible to see that the road was not clear of oncoming traffic, possibly depending on the other driver noting that his truck was in the intersection and slowing. 2) "Autopilot", as implemented on production Teslas in the public's hands, is not designed to work with objects that are not moving along marked lanes in roughly the same direction and at about the same speed as the Tesla being so piloted. That is, it cannot cope with cross traffic and was never designed to operate on any roads that are not limited, ramp-accessed highways. It pays no attention to cross traffic. It pays no attention to unmoving objects, it cannot detect walls and trucks don't look like "vehicle" to it from the side. There is (in plain body text, not a warning) mention in the owners manual that this function is only to be used on restricted-access roads, and the fellow that was there that seemed to be taking the role of "representative of Tesla" admitted that they should probably be using map and GPS data to prevent activation of driving assistance functions when not on appropriate roads, and to disable it if the driver were to leave those roads. (It's LONG. I got in about 40 minutes late, listened for about 45 minutes, then they were taking a break and going to reconvene when I had another call to take.)I believe that the NTSB will blame the driver as the main culprit for not watching the road while the Autopilot was in operation. Then Tesla Motors may get blamed for not adding hardware and software that is watching and warning the driver. Cadillac will offer next month its "Super Cruise" that allows full hands free driving in the CT6 but it watches the driver at all times. An accident like this can happen but it is fully the driver's fault if there is no human reaction.
May have updated since, because 21 hours ago was probably when they were finishing up and rendering the archive video.I don't see any relevant links on that site(?).
I think this article gives a decent summary: https://arstechnica.com/cars/2017/09/ntsb-teslas-autopilot-ux-a-major-role-in-fatal-model-s-crash/