What if???

[Scooby]

My football crew met up with another crew tonight, at a local watering hole, and they said that they had this play. B55 encroachment and the Line Judge threw a flag, but did not shut down the play, during the play A10 blocked in the back. How is this enforced? Do you ignore the block in the back since the play should not have been run? Is there something in the rule book that give direction on this play?