In the cop's initial assessment of this event, based upon what they were told, they believed that a very basic assault might have occurred.

They referred the information they gathered to higher-ups to further evaluate it to see if there was actually a prosecutable offense that occurred.

It doesn't look like there was, since no ongoing prosecutions seem to be happening. But even if they do, it's a minimal thing. Heck, one can be charged with third degree 'assault' if you get teed off at another driver and spit on their window, for cripes sake.