Situation (in a youth baseball league game): Bases loaded, 1 out.
A ground ball is hit to the shortstop. Runner at 3rd goes home and touches the plate. Runner at 2nd begins to run to 3rd, but seeing the SS with the ball retreats back toward 2nd, but is tagged out. Meanwhile the runner at first had gotten to 2nd base, but seeing the runner ahead of him retreating, began running back to first. He is then tagged out for the 3rd out of the inning. The umpire rules that the run doesn't count, as the runner who had started at first had brought the force play back into effect by retreating.
Was this ruling correct?