CA Gov't Code Section 110021

If a predecessor agency is party to any memorandum of understanding or agreement with any bargaining unit that includes individual providers that contains an agency shop provision as of the effective date of this title, the predecessor agency and the employer shall be obligated to honor the terms of the agency shop provision, including indemnification provisions, if any, for the duration of the memorandum of understanding or agreement, and until the adoption of a successor memorandum of understanding or agreement. However, upon the request of a recognized employee organization, an agency shop provision in effect on the county implementation date may be reopened for the sole purpose of renegotiating the terms of that provision in accordance with this title. The implementation of this title shall not be a cause for a new agency shop election.