Hi, welcome to osm. You have been adding invalid multipolygons. 
https://tools.geofabrik.de/osmi/?view=areas&lon=152.34933&lat=-24.86866&zoom=14
There are examples of invalid types here
https://wiki.openstreetmap.org/wiki/Relation:multipolygon
You should use building:part relation kind instead or else use delete all the multipolygons and use simple polygons to draw each section.