Hi ProTrollface,
th9s changeset has created several errors in the OSM database regarding duplicate nodes and overlapping buildings:

https://tools.geofabrik.de/osmi/?view=geometry&lon=-2.93164&lat=37.60970&zoom=16&baselayer=Geofabrik%20Standard&overlays=self_intersection_ways%2Cself_intersection_points%2Csingle_node_in_way%2Cduplicate_node_in_way

https://overpass-api.de/achavi/?changeset=133862559

So more or less all buildings you have added are duplicated now.

Can you please fix this?
Kind regards
Guido