Opinions needed, OBR rules

[BK47]

if the PU has a strike three and the ball is obviously in the dirt and/or rolling away then I would think that most (I say most because some smaller guys such as 9-12 may not know) would know to start running right away to first. The catcher would also know right away to get the ball and either tag the BR out or throw to first. There I would say should be no problem unless the PU was sleeping and didnt know it was in the dirt and rolling around or away from the catcher.

I read this post as PU initially had a clean strike three. What made him change his mind to a dropped strike three? If he thought from the getgo that it was clean and he sold it so when he punched the batter out what would make him change his mind? Am I missing something? Did the BU signal to him that it was a dropped strike three?