Here's a simple query, it's expected to return "apache-spark", as https://www.wikidata.org/wiki/Q7573619 indeed has "Repology project name" (P6931) property, which was added some over 3 weeks ago.

SELECT ?repology_project {
  wd:Q7573619 wdt:P6931 ?repology_project .
}

However, the result is empty: https://w.wiki/6X2, and it seems to me that there's a bug somewhere.

To confirm that the query is correct, similar query works fine with another entry:

SELECT ?repology_project {
  wd:Q189248 wdt:P6931 ?repology_project .
}

This expectedly returns "bash": https://w.wiki/6X3.