Umpire Not Coach I Know But..

[RulesGeek]

Originally Posted by MD Longhorn

It's clearly a no-stop balk. But at the JV level, while I agree we aren't there to coach - letting a balk like this go in cases where it's really not affecting anyone is the prudent action. But you DO need to let the coach know so he can fix it.

Speaking OBR, not sure about NFHS.
I agree balk.
One oddity is that if I am picturing OP situation correctly pitcher is using the windup even with runners on base.
So I'm not getting him for not stopping.
I've got him for a quick pitch and thus illegal ..... so results in a balk if runners are on base. It's not exactly the situation described in the comment 8.01 but I believe the coment applies. ("Pitchers ... may not step quickly onto the rubber and pitch.")

don't need to wait until there is a runner on and things mught be a little tense either. It is a ball on hitter 1, pitch 1 (unless he puts it in play & reaches) so the problem is addressed early, with a minor penalty.