I don't want to post any more potentially false-positive bug reports, but are [[meta:Main Page]] and [[wikidata:Wikidata:Main Page]] interwikilinks not supposed to work as well? http://nicoleruizsharp.altervista.org/wiki/index.php?title=NikkiWiki:sandbox#interwiki

Thank you for the info. I thought it was a bug because all of the other interwikilinks from English MediaWiki go by default (without a language tag) to the English subdomain for the language-subdomained Wikimedia projects.