I guess the existing building, which comes from an old import (https://www.openstreetmap.org/way/246544847) is completely outdated and should be deleted.  So should the two adjacent buildings on its right side.

Buildings in UrbisAdm looks closer to the truth, might be worth importing.

But I guess you are right: some buildings appear to be missing, e.g. the one at this location: 50.8519902 4.3257229