Anything done by or in relation to a person purporting to act under an appointment (including an acting appointment) under an Act is not invalid merely because:
(a) for any appointment--the occasion for the appointment had not arisen; or
(b) for any appointment--there was a defect or irregularity in connection with the appointment; or
(c) for any appointment--the appointment had ceased to have effect; or
(d) for an acting appointment--the occasion to act had not arisen or had ceased.