“One of the issues that we continue to have issues with is false positives. We've had 39 false positives, where that means 39 people missing practice. And we're at I think a higher rate than anybody in the conference and we're trying to find out why, because every time we have one of those guys, they miss a practice,” Penn State coach James Franklin said, expressing relief that they haven’t been actual positive tests. “We've had a few kids as well as staff members that have gotten false positives multiple days in a row," per PSU Rivals site article.
It impacted Stanford big time, apparently in opener with Oregon.