Originally Posted by DownInPetaluma

If there was even a tiny hint of tire cornering force after touchdown there would be a slight, perhaps imperceptible upwind weathervaning that would be enough to split the reverse vector and get the airplane moving downwind. If you look closely there is a drift to the right, correction to the left, increase in reverse, and finally the complete swing into the wind as the tail is pushed by the increasing vector and wind itself.

All true- what you said. Could be any one of us, unfortunately.