When using nominatim i noticed some villages in Spain do not have associated province such as: “El Burgo de Osma”
This village belongs to the province of “Soria”. This province exists in OSM:
However it is not found in nominatim:Nominatim Demo
I would say that it is not a problem of nominatim, but of OSM. My theory is that relationships should be edited in OSM but I don’t know how. Could someone confirm it? Thanks