Source: http://friendsofprop64.org/prop-64-protects-medical-marijuana-law/
Timestamp: 2019-04-19 10:35:45+00:00

Document:
Proposition 64, the marijuana legalization initiative on the November 2016 ballot, does not change the Prop 215 medical marijuana defense.
Courts have since held that this means any amount reasonably related to the patient’s medical needs (People v Kelly) and includes a defense against transportation charges if the quantity is reasonable to the time frame and circumstances (People v Trippet). Local governments may, however, adopt civil ordinances that ban collectives (Inland Empire Patients v Riverside) and even personal medical cultivation (Maral v Live Oak) but patients still retain the immunity defense in criminal court (Kirby v Fresno).
Currently and as revised in Prop 64, H&S §11357 (a) begins by saying: “Except as authorized by law,” while 11358 states in mid sentence, “except as otherwise provided by law.” So the limits on non-medical use and cultivation in Prop 64 took into account the provision to exempt medical marijuana patients. While Prop 64 does eliminate or reduce some of the penalties for violating the statutes, it doesn’t affect the medical use exception.
Furthermore, Prop 64 protects Prop 215 at least nine times. Five sections reinforce the current laws [§11362.2(b)(2) legalizes home cultivation, §11362.3(f) preserves patient rights related to Prop 215, §11362.45(i) again preserves Prop 215 and related laws and case law, §11362.712(a) protects patients’ cannabis recommendations, §26067(e)(1) exempts medical and non-medical home grows from commercial tax and regulation]. Four sections create new rights [§11362.84 patient custodial rights, §26054.2(a) licensing priority for existing collectives and dispensaries, §34011(g) patients exempt from state sales tax and §34012(j) patient gardens exempt from state production tax.
California Prop 64 section 11362.45 makes its strongest case when it reiterates, “Nothing in section 11362.1 shall be construed or interpreted to amend, repeal, affect, restrict, or preempt: (i) Laws pertaining to the Compassionate Use Act of 1996.” That includes the SB 420 safe harbor from 2003 and the Medical Cannabis Regulation and Safety Act as recently adopted by the state legislature. You can take that one to the bank.

References: §11357
 §11362
 §11362
 §11362
 §26067
 §26054
 §34011
 §34012