No act done by a person as a director shall be deemed to be invalid, notwithstanding that it was subsequently noticed that his appointment was invalid by reason of any defect or disqualification or had terminated by virtue of any provision contained in this Act or in the articles of the company:
     Provided that nothing in this section shall be deemed to give validity to any act done by the director after his appointment has been noticed by the company to be invalid or to have terminated.