Is it generally misconduct for a jury to discuss a defendant's failure to testify?

It is generally misconduct for a jury to discuss a defendant's failure to testify. (People v. Loker, supra, 44 Cal.4th at p. 749.) Such misconduct creates a presumption of prejudice which may be rebutted by a finding that there is no substantial likelihood the complaining party suffered actual harm. (Ibid.) "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." (Id. at p. 747.)