If the director issues a final decision that includes a finding that a contractor violated RCW 39.12.065 and that the contractor owes unpaid prevailing wages, and the finding is not timely appealed or is affirmed by the courts, the findings and the decision are res judicata in any action by the department or by any interested party who was a plaintiff at the hearing, against the contractor and its sureties to recover the unpaid prevailing wages. The findings and decision are not res judicata in any action by an interested party who was not a plaintiff at the hearing.