What standard of prejudice applies to a failure to give a unanimity instruction?

^6. Courts are divided on the standard of prejudice to apply to the failure to give a unanimity instruction, with some applying the state law standard of People v. Watson (1956) 46 Cal.2d 818, 836, and others the standard for federal constitutional error in Chapman, supra, 386 U.S. at p. 24. (See Hernandez, supra, 217 Cal.App.4th at pp. 576-577 [discussing split].) We follow the majority in applying the Chapman standard, concluding that failing to give the unanimity instruction can lower the prosecution's burden of proof in a criminal case, an error of federal constitutional dimension. (See Hernandez, at p. 576.)