Nominatim search bug (can't find house)

I’m investigating Nominatim and looked in update delay for search of newly added houses. During talks in our local community i’ve found that we have

Where first one is searchable and second is not - but they have almost identical tags and was added in same commit.
You can search first by:
9 Metrobudivnykiv Kharkiv

but second isn’t searchable by
11 Metrobudivnykiv Kharkiv

Can anyone explain what is wrong here?

I’ve looked around it and found that when data is indexed after import at gazetteer-index.sql

update placex set indexed = true where not indexed and rank_search = 21 and name is not null;

don’t know why - it checks only if name is set - anyone knows why?