Flight groundings on June 8 and 9 were caused by a software glitch in some Collins GPS receivers found in bizjets and a few airliners. At issue was the receivers’ failure to compensate for the “leap second” applied to the almanac data every two and a half years.
This is a companion discussion topic for the original entry at https://www.avweb.com/news/collins-gps-errors-spark-flight-delays