Texas Government Code - GOV'T § 1371.059. Validity and Incontestability

(a) If proceedings to authorize an obligation or credit agreement are approved by the attorney general and registered by the comptroller, each obligation or credit agreement, as applicable, or a contract providing revenue or security included in or executed and delivered according to the authorizing proceedings is incontestable in a court or other forum and is valid, binding, and enforceable according to its terms.

(b) Notwithstanding Subsection (a) and Section 1371.003, and except as provided by this subsection, an obligation authorized by this chapter is not valid, binding, or enforceable unless the obligation is approved by the attorney general and registered by the comptroller in accordance with Chapter 1202. The attorney general's approval and registration by the comptroller is not required for an obligation:

(c) An issuer in the proceedings to authorize obligations or a credit agreement, or in a credit agreement, may agree to waive sovereign immunity from suit or liability for the purpose of adjudicating a claim to enforce the credit agreement or obligation or for damages for breach of the credit agreement or obligation. This subsection does not apply to an issuer that is: