Data extension: sitelinks (Wikidata) are sometimes not shown/extracted, while they do exist

[trnstlntk]

In OpenRefine projects with at least one column reconciled to Wikidata, sitelinks (retrieved through data extension using S.... syntax) are only partially retrieved.

To reproduce:

1. Take any OpenRefine project with at least one column that's reconciled with Wikidata
2. Ask to retrieve sitelinks from that column (Edit column > Add column from reconciled values... > type Snlwiki or other wiki name per documentation)

Current result

Data extension preview dialog sometimes produces an 'Error.' message (sometimes not). When adding the new sitelink column, it will provide some sitelinks, but alas not for all items that have one available.

Expected result

Sitelink data extension should return all valid sitelinks for the provided wiki

Dataset for reproducing

This one:
public-art-NL-for-SDC.openrefine.tar.gz
in which I tried to retrieve Snlwiki sitelinks for the reconciled item column.
A few example items where, in my case, Dutch Wikipedia sitelinks were not shown, while they do exist: Q2084947, Q2177029, Q17440241.