28 CCR §1300.67.13(a)(2-3)

(2) A COB provision may not relieve a plan of a duty otherwise arising from a plan contract to deliver any health care service to any subscriber or enrollee because the subscriber or enrollee may be or is entitled to coverage for the service by any other plan or insurer.

(3) A COB provision may not result in a delay in furnishing any reasonably necessary health care service to any subscriber or enrollee pursuant to a plan contract.