This is because the title was imported from Wikidata when I added the Wikidata ID:

https://www.wikidata.org/wiki/Q77980366

The building is a heritage listed building, but the name listed by Heritage NZ is literally just "House".

https://www.heritage.org.nz/list-details/2174/2174

Often if Heritage NZ does additional research, they'll add a more specific name for a feature that they've given a generic name. Hopefully that happens one day for this.