Section 12. Certain acts not to be invalid

12. No consultation made with the Commission, or advice tendered by it, or examinations held by it or result at such examination or interviews conducted by the Commission or any Interview Board, or proceeding of the Commission or of any Interview Board shall be rendered invalid merely on the ground of- (a) any defect in appointment of the Chairman or any member of the Commission or in constitution of the Interview Board, or (b) any vacancy in the Commission or any of its Committees or Interview Board, or (c) any defect or irregularity not affecting the substance in any proceedings before the Commission, Committee or the Interview Board.