It seems to me like it only reports location when the case is opened, resulting in issues like this. I had a similar thing happen where Find My said they were at work, but in fact they were at home. Just hadn’t opened the case in several hours.
Piggybacking on this, it would be a lot easier if we could block communities from the main feed rather than having to go directly to the community and then block them.
Well it is a magical place you know