Compiling Spain I get several warnings similar to the one below, that point to data that are correct (or it seems to me).

2010/02/12 09:26:39 ADVERTENCIA (MultiPolygonRelation): 63240004.osm.gz: Multipolygon http://www.openstreetmap.org/browse/relation/319017 contains errors.
2010/02/12 09:26:39 ADVERTENCIA (MultiPolygonRelation): 63240004.osm.gz: Polygon 4611686018427391078[5P : (44132028[5P]) carries role inner but is not inside any outer polygon. Potentially it does not belong to this multipolygon.

Reported way (hole in the building) lacks in the resulting map.
Is it a know bug?
Another question, why are polygons so deformed in MapSource compared to Mapnik?