California Code, Education Code - EDC § 22461

(a) Upon retaining the services of a retired member under Section 24114, 24116, 24214, 24214.5, or 24215, the school district, community college district, county superintendent of schools, California State University, or other employing agency shall do both of the following regardless of whether the retired member performs the services as an employee of the employer, an employee of a third party, or an independent contractor:

(b) This section shall not be construed to make any school district, community college district, county superintendent of schools, the California State University, or other employing agency liable for any amount paid to the retired member in excess of the earnings limitation under any circumstance, including the failure to inform the retired member that continuation of service would exceed the limitations.