From @Elitre:
Per Diwas:
"https://phabricator.wikimedia.org/T178976 is with the New wikitext mode, not the WYSIWYG mode. Be sure that beta feature New wikitext mode and Spezial:Einstellungen#mw-prefsection-editing: Temporarily disable the visual editor while it is in beta are checked. You will be have only one edit link Edit, but not Edit source. The Link Edit will start the New wikitext mode. But with a redirect page it will open the target page, not the redirect page."
I can finally reproduce this issue.
Previously also reported at mw.org.