(a) Except as provided by Subsection (b), in an authority in which the principal municipality has a population of less than 1.3 million or more than 1.9 million, an action of the board is not invalid because a ground for removal of a board member exists.
(b) An action that was taken when a ground for removal under Section 451.510(4) existed and that would not have passed the board without the vote of the person who is the subject of the ground for removal is voidable.