Using the latest release 230514-0b780defb - manually setting coordinates of pictures without GPS data in their exif and filtering by unknown country still shows these pictures, even though when opening them - they have a country set in the UI.
Note that this wasn't the behavior in older releases - I'm using the "unknown country" filter a lot in order to tag (mostly) older pictures without GPS data.
Using the latest release 230514-0b780defb - manually setting coordinates of pictures without GPS data in their exif and filtering by unknown country still shows these pictures, even though when opening them - they have a country set in the UI.
Note that this wasn't the behavior in older releases - I'm using the "unknown country" filter a lot in order to tag (mostly) older pictures without GPS data.