Here is an interesting state case out of the 12th Appellate District of Ohio, Ohio v. Montiero. In Montiero, both defense counsel and the prosecution became aware, during voir dire, that one of the jurors was not a U.S. citizen, but rather a Canadian citizen. However, neither attorney struck the juror.
After the defendant was convicted for Operating a Vehicle Under the Influence, he appealed based on the presence of the Canadian juror. Defense counsel argued that the presence of the Canadian on the jury created a structural error as the case was only decided by 7 out of the 8 qualified jurors selected to hear the case. The appellate court affirmed the defendant's conviction finding that the defense counsel should have struck the Canadian juror if he didn't want him to serve. Furthermore, the appellate court did not see the presence of the Canadian as a structural error. Rather, it found that the alleged error here involves a statutory violation under R.C. 2313.42, and not a constitutional right (see Section 5, Article I, Ohio Constitution: "The right of trial by jury shall be inviolate, except that, in civil cases, laws may be passed to authorize the rendering of a verdict by the concurrence of not less than three-fourths of the jury"), we cannot conclude the trial court's oversight involves structural error.