I think the problem is that there is a multipolygon where the multipolygon and the inner line of it are both buildings.
A multipolygon in meant to for area’s with holes in the middle, e.g. a island in a lake or a building with a garden in the middle.
I don’t really understand what you try to achieve here. Is it only the center part of the building that has a certain name or address ?
Wouldn’t it be ook to put all details on the outer line ?