law: 55. Vacancies, etc., not to invalidate proceeding of Appellate Tribunal.-
  No act or proceeding of the Appellate Tribunal shall be invalid merely by reason of-
  (a) any vacancy in, or any defect in the constitution of, the Appellate Tribunal; or
  (b) any defect in the appointment of a person acting as a Member of the Appellate Tribunal; or
  (c) any irregularity in the procedure of the Appellate Tribunal not affecting the merits of the case.