Unexpected objects in search results for a building address

[rpahut]

Discussed in #3602

Searching for some building addresses with layer=ADDRESS in a DB imported with NOMINATIM_IMPORT_STYLE=address yields, on top of the building at the address, other unexpected POI-like objects.

Examples:
N5266350421, N5266417321 for address (now removed).
N4682629046 for address.

The expected behavior is for POIs to be absent in a DB imported with NOMINATIM_IMPORT_STYLE=address, or if they has to be present, not be returned alongside the exact address match when there is one, or if they has to be returned, to be practically distinguishable from the exact address match.