Tenn. Code § 7-82-504
Such bonds bearing the signatures of officers in office on the date of the signing of the bonds shall be valid and binding obligations, notwithstanding that before the delivery of the bonds and payment for the bonds any or all the persons whose signatures appear on the bonds shall have ceased to be officers of the district issuing the bonds. The validity of the bonds shall not be dependent on nor affected by the validity or regularity of any proceedings relating to the acquisition, purchase, construction, reconstruction, improvement, betterment, or extension of the utility for which the bonds are issued. The resolution authorizing the bonds may provide that the bonds shall contain a recital that they are issued pursuant to this chapter, which recital shall be conclusive evidence of their validity and of the regularity of their issuance.
T.C.A. § 7-82-504