Can a jury be found to have breached their instruction not to discuss appellant's failure to testify during deliberations by discussing the appellant's refusal to testify?

Several jurors violated the instruction during deliberations by discussing appellant's failure to testify. The trial court correctly found this to be juror misconduct, which gave rise to a rebuttable presumption of prejudice. (See People v. Leonard (2007) 40 Cal.4th 1370, 1425.)

We may reverse the judgment only if we find that the misconduct was prejudicial. (People v. Loker (2008) 44 Cal.4th 691, 746.) "Whether prejudice arose from juror misconduct is a mixed question of law and fact. We review legal issues independently, and accept the trial court's factual findings if they are supported by substantial evidence. [Citation.]" (Id. at p. 747; see also People v. Nesler, supra, 16 Cal.4th at p. 582.)

In sexual molestation cases, a discussion of defendant's decision not to testify may carry a high potential for prejudice, particularly when there is no physical evidence, and the issue of guilt turns largely on the victim's credibility. (People v. Cissna (2010) 182 Cal.App.4th 1105, 1121.) Thus, when the discussion is more than transitory and jurors repeatedly ignore their instruction not to discuss the subject, there is a substantial likelihood that the offending jurors' impartiality will be compromised. (Id. at pp. 1121-1123.)