I have a friend that I’m competing against who went from ~95% complete to ~40% complete in our town. She hasn’t turned anything off, and her runs are still syncing as I can see runs from this week. She’s a strava user. Can you see where the missing runs went?
Strava is now connected to their account, so that’s likely the reason. It definitely sounds like they revoked access (which deletes that data in CityStrides) and then reconnected.