N.D. Cent. Code § 52-06-21
Any right, fact, or matter in issue directly passed upon or necessarily involved in a determination or redetermination which has become final, or which has become final following a decision or appeal under the North Dakota unemployment compensation law, is conclusive for all the purposes of the North Dakota unemployment compensation law as between the bureau, the claimant, and all employing units who had notice of such determination, redetermination, or decisions. Any determination, redetermination, or decision as to rights to benefits which has become final and conclusive in accordance with this section is not subject to collateral attack by any employing unit, irrespective of notice. As used in this section, "collateral attack by any employing unit" includes a collateral attack by a reimbursing or contributory base-period employer on a final and conclusive determination of benefits involving a different employer provided that an employer challenging the propriety of charging any benefits paid as a result of a final determination, redetermination, or decision is entitled to receive data and information from job service North Dakota concerning the monetary basis for the claimant's right to the benefits at issue. Provided further, that at any hearing on the challenge, job service North Dakota is not required to call or subpoena the claimant or the claimant's last or most recent employer as a witness.
N.D.C.C. § 52-06-21