Tex. Bus. Orgs. Code § 21.909

On or after the validation effective time, unless determined otherwise in an action brought under Section 21.914 and subject to Sections 21.902(b) and 21.907(e), each defective corporate act ratified in accordance with this subchapter may not be considered ineffective, void, or voidable as a result of the failure of authorization described by the resolutions adopted under Sections 21.903 and 21.904, and the effect shall be retroactive to the time of the defective corporate act.