When you visit https://en.wikipedia.org/wiki/Beatles , it displays "redirected from _The Beatles_ ( Article->showRedirecteFromHeader adds a div #contentsub with the 'redirectedfrom' message.)
Flow doesn't implement any of that.
To reproduce, visit http://ee-flow.wmflabs.org/wiki/Sandbox2 which is a #REDIRECT to [[Sandbox]]. You see the Sandbox Flow board, with no indication that you've been redirected except that the H1 title doesn't match the title in the URL
Somehow the JsonSchema content type handles this correctly, see https://meta.wikimedia.org/wiki/User:S_Page_%28WMF%29/TestSchemaRedirect Maybe class WikitextContent is doing the work.