The validity of the authorization and issuance of any bonds by the commission is not dependent on or affected in any way, except to the extent provided in the indenture by:
(a) Proceedings taken by the commission or the department for the acquisition, construction, or completion of the regional transit terminal or any part thereof.
(b) Any contracts made by the commission or the department in connection with the acquisition, construction, or completion of the regional transit terminal or any part thereof.
(c) The failure to complete any part of the regional transit terminal for which bonds are authorized to be issued.