Android has three options for allowing Grindr to access the location: all the time, only while using the app, and deny. The issue presents itself as Grindr being unable to acquire your location and then failing to update the grid when the access is "only while using the app". The solution appear to be to update the manifest to request the ACCESSBACKGROUNDLOCATION, thereby allowing the option. This should prevent the error I see frequently when returning to the app.
The workaround is to force quit Grindr and relaunch.