On fiwiki a user moved a page to article namespace with "Wikiprojekti"-prefix, before than Wikiprojekti namespace was created in https://phabricator.wikimedia.org/T156621. Now https://fi.wikipedia.org/wiki/K%C3%A4ytt%C3%A4j%C3%A4:Wikiprojekti:Lappeenrannan_Wikikoulutus redirects to the page that is in article namespace (see https://fi.wikipedia.org/wiki/Special:AllPages?from=Wikiprojekti&to=&namespace=0). We can't move that page to Wikiprojekti namespace.
Of course we could copy paste the content, but is it possible to move the page along the history?