Everything looks set up correctly on Wikidata and our end, but our Wikipedia links are very buggy. It’s possible that manually setting the Wikipedia page would fix things, but I doubt it.
We shouldn’t need to manually set the Wikipedia link in most cases. The page should be automatically pulled in for a given language if the Wikidata page is set up correctly. But I have been seeing instances recently where this isn’t happening properly.
Wikidata collects all Wikipedia pages across languages into one place. iNat taxon IDs can also be entered there so the pages are linked properly for our display (that is at least how it is supposed to work). See: https://www.wikidata.org/wiki/Q25380