Baserunning question - little league

[recoachtn]

I have a little league (seniors) baserunning rules question.

Runners on first and second. Batter gets basehit to right field. Runners advance. Throwing error has lead runner heading to home and middle runner heading to third. Lead runner touches home but, due to confusion of coaches/parents yelling "back, back" (meant for middle runner now rounding third), lead runner heads back to third base. Middle runner heads home and passes lead runner now heading back to third. Fielding team tags both runners.

Ruling - Both runners are safe and runs count.

Question: Shouldn't one of the runners be out either because the middle runner has now passed the lead runner or for play interference by inappropriately reentering the field of play?

Nobody at the game has ever seen this happen after the lead runner has crossed home plate. Neither umpire seemed sure of the correct ruling or rule.

If anybody can tell me what the correct ruling should have been and, if possible, the rule that governs, I would greatly appreciate it.