Notice of a determination upon a claim must be given promptly to the claimant by delivery thereof or by mailing such notice to the claimant’s last-known address. In addition, notice of any determination which involves the application of the provisions of section 52-06-02 together with the reasons therefor, must be given promptly in the same manner to the last employing unit by whom the claimant was employed. The bureau may dispense with the giving of notice of any determination to any employing unit and such employing unit shall not be entitled to such notice if it has failed to indicate prior to the determination if and as required by regulation of the bureau, that such employing unit was the claimant’s base-period employer, as defined in the North Dakota unemployment compensation law, and that the claimant may be ineligible or disqualified under any provisions of the North Dakota unemployment compensation law.