Does a juror have to be excused from a jury for failing to follow their instructions?

(1996) 46 Cal.App.4th 1767, 1780-1781 [a juror was properly discharged for being unable to comprehend simple concepts or remember events during deliberations such as recent discussions or votes, and was not following the law]; People v. Collins (1976) 17 Cal.3d 687, 690-693 [trial court properly discharged a juror who said she was unable to follow the court's instructions and "felt more emotionally than intellectually involved" in the case and wanted to be excused].)