How have the harmless error rule been interpreted in the context of a jury finding that a judge improperly submitted a self-defense claim to the jury?

[192 Cal.App.3d 634] I agree with the scholarly dissent of the late Justice Sims in People v. Dagnino, supra, 80 Cal.App.3d 981, 990, 146 Cal.Rptr. 129, that the harmless error rule should apply to unauthorized communications between judge and jury. But even by that yardstick, reversal is compelled because the judge on his own submitted a self-defense theory to the jury which undermined the defendant's contention that the officer was injured accidentally and by inadvertence.