As reported by an editor: "be-x-old Wikipedia has been renamed as be-tarask, but wikidata interwikis still contain be_x_old [...] Bots display an error:
WARNING: pywikibot-core/pywikibot/site.py:1897: UserWarning: Site wikipedia:be-tarask instantiated using different code "be-x-old"
Screenshot from Wikimedia main page