Did the Arizona Supreme Court err when, like a substantial number of courts throughout the country, it violated the rule contained in Court's decisions in Mattox v. United States, 146 U.S. 140, 13 S.Ct. 50 (1892), and Remmer v. United States, 347 U.S. 227, 74 S.Ct. 450 (1954), by shifting the burden of proof of harm to the defendant even though a juror had presumptively-prejudicial, inadmissible, external evidence during the defendant's trial and shared it with other jurors?

Did the Arizona Supreme Court err by shifting the burden of proof of harm to the defendant after a juror was exposed to inadmissible external evidence during trial?