Cal. Pub. Util. Code § 17008

Notwithstanding the fact that an officer whose signature, countersignature, or attestation appears on any bonds or coupons thereof ceases to be such officer before the sale or delivery of such bonds, his signature, countersignature, or attestation appearing either on the bonds or the coupons, or on both, is valid and sufficient for all purposes the same as if he had remained in office until the sale or delivery of the bonds.