The world-wide GPS system once every 20 years Week Number Roll Over happened last night.
Per the good folks at Garmin:
https://support.garmin.com/ms-MY/?faq=zWQY6Z2kFiAuY9kDnDBgZ6
My portable TomTom car unit also needs a software update:
https://www.tomtom.com/en_us/updates/