I have exactly the same problem, the app is still reporting screen time when I look at the list view, but everyone in my family says "We couldn't find their location"
This worked perfectly until maybe a couple of weeks ago, however I have some location alerts configured and the weird thing is I still get them so it must be partially working, but I can't see their location on the map.
I'm an IT veteran and know how to troubleshoot, I've done the usual including uninstall/reinstall etc, Everything worked fine until recently and nothing has changed on my side.
Logging into the Family on a browser however does show the location, so the issue must be the Android app - but the last time it was updated on the Play store was 15 Dec 2022 and it's been working after that until late Feb / early March.
I've emailed the team directly using the email address provided in the Play store, maybe worth others doing the same familysafetyfeedback@microsoft.com