More reports coming in do make better sense.
I do think it was caused by a nut (or two) behind the wheel.
No telling what happened. I drove a freighter for a while. In some cases the person who cause or nearly cause a chain reaction wreck never even realized what happened and drive on.
There’s a link at the top of the thread to some news reports. They were talking to a girl who was in front of the tanker and watched the wreck in her rear view mirror. Said she just passed the truck and the truck veered into the center divide right behind her.