The Commission shall excuse a failure to comply with the notice requirement of § 9-704 or § 9-705 of this subtitle if the Commission finds that: there was a sufficient reason for the failure to comply; or the employer or its insurer has not been prejudiced by the failure to comply. The employer or its insurer has the burden of proving that it has been prejudiced by the failure to comply with the notice requirement. In the case of an occupational disease, the defense of failure to comply with the notice requirement is waived unless raised at a hearing on the claim before any award or decision is made.