Prior to 2016 CC 548 simply informed the jurors that: “You do not need to agree on the same theory [of murder].” However, in People v. Sanchez (2013) 221 Cal.App.4th 1012, 1025 recognized that giving such an instruction may be reversible error if the different theories of guilt result in different degrees of guilt:
Unanimity was required in this case as to the theory of guilt as a result of different theories supporting different degrees of murder. The prosecutor understood the need for unanimity at the time he requested instructions on natural and probable consequences, specifically telling the trial court the jury could return a verdict of murder in the first or second degree, depending on what theory they unanimously agreed upon.
(Sanchez, 221 CA4th at 1025.)
Accordingly, in 2016 CC 548 was revised as follows:
You may not find the defendant guilty of murder unless all of you agree that the People have proved that the defendant committed murder under at least one of these theories. You do not all need to agree on the same theory[, but you must unanimously agree whether the murder is in the first or second degree].
The Committee notes state: “The brackets around the new language indicate that it is optional, to be given in the court’s discretion.”
See https://jcc.legistar.com/View.ashx?M=F&ID=4256649&GUID=4F153BB2-31D2-4B98-8257-04865BAFD5E3