Inconsistent results for searches on postal_code areas - data problem or Nominatim issue?

I live in Belgium, which has a complete coverage of boundary=postal_code areas. (At least in the part of the country I will now be talking about.)

Typing “1410, Belgium” in the search box will correctly link to a “postal code” relation with that postcode: Relation: 4727648 | OpenStreetMap

Surprisingly, most postal code relations in and around Brussels can no longer be found, despite they exist in the database.
Typing “1083, Belgium” will not link to the desired relation, whereas Relation: 3379420 | OpenStreetMap was expected. AFAIK, until recently this worked fine.

Also, Brussels city centre has postcode 1000 (Relation: 3379410 | OpenStreetMap) but Nominatim will ignore this relation and return postcodes from other municipalities, e.g. this incorrectly returns postcode 1060:

I inspected postal code relations: they look properly tagged, ways are ordered properly, no gaps, and areas do not overlap.

How can I see whether the problem is with OSM data or if this is a problem with Nominatim?

It seems that you just fixed the boundaries in question a couple of days back. It could very well be that these do not get indexed immediately, I’ve asked Sarah to clarify.

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Fixed in Flex style: reinstate postalcode relations by lonvia · Pull Request #3021 · osm-search/Nominatim · GitHub. I’ll have a look at reinstating the postcode boundaries in Brussels on the production servers as soon as the change goes live.


Indeed, Nominatim can now retrieve postal code areas without a name. Queries work fine again. Thanks a lot @lonvia for the fix!