Any irregularity in the method or scope of assignment of a civil action or proceeding to any magistrate under the Idaho Court Administrative Rules and Idaho Code Sections 1-2208 and 1-2210, and all objections to the propriety of an assignment to a magistrate are waived unless a written objection is filed before the trial or hearing begins. No order or judgment is void or subject to collateral attack because it is rendered pursuant to an improper assignment to a magistrate.