As noted above, the University of California is given special status by a section of California constitution, so it has special status through that. It's presumably clauses like that fact it's governed by the Regents "...subject only to such legislative control as may be necessary to insure the security of its funds and compliance with the terms of the endowments of the university..." that mean it isn't normally affected by new laws.

(https://leginfo.legislature.ca.gov/faces/codes_displaySectio...)