You are being redirected

I have done something to my application controller so that instead of
the redirected page itself am now seeing this as a response:

<html><body>You are being <a href="http://www.example.com/
welcome">redirected</a>.</body></html>

I do not know why this is happening or what I did to trigger this
behaviour. The API does not give me any clues as to what is going
on. The redirect command involved is:

redirect_back_or_default(welcome_path)

    def redirect_back_or_default(default)
      redirect_to(session[:return_to] || default)
      session[:return_to] = nil
    end

Up to today this has simply displayed the target page. I have no idea
how or why the intermediate redirect page is generated. I would be
very grateful if anyone can enlighten me on this matter.