Don't think I've seen this before... U3K, batter busts out of the righty's box, stumbles & falls just beyond the lefty's box, gets back up just in time to get hit in the back of the helmet with the throw from F2.
My partner has a no-call, slight grumbling from the DC. but had me thinking about ASA 8.2.F.3 (no, couldn't quote that line and verse at the time

)
She clearly hadn't reached the 3' lane yet, but that's not mentioned in this rule.
Any comments would be appreciated.