This interpretation was posted on 4/30/19:
The offensive team:
6.5.3 Must keep all personnel, except the base coaches, batter, base
runner(s) and on-deck batter, in the dugout, bullpen or dead-ball
area while the ball is live.
EFFECT: The umpire shall warn the violator(s), and if the violator(s) does not immediately comply, the umpire should eject him or her. (Administrative ejection; see Rule 13.2.1)
Interpretation: After receiving a warning for being out of the dugout, bullpen or dead-ball area on a live ball, the next violation of this rule by anyone of the warned team will result in the ejection of the head coach.