Web site rule redirection problem when already authenticated

I use a web site redirection rule to redirect a user-friendly URL to the actual URL for one of my applications.

So this: https://www.blah.com/aaa

redirects to this: https://www.blah.com/bbb/aaa.nsf/Home?OpenForm

Generally speaking, it works fine. The user is prompted to log in (I use session-based authentication) and then the application’s Home page opens.

However, if the user is already authenticated (say they have opened a second tab in the same browser session), they are not prompted to authenticate and while the home page opens, the URL in the browser’s address bar remains the shortcut url www.blah.com/aaa. So then all the relative links fail.

Any ideas why the address in the browser is not resolving to the real database location? Any suggestions on how to fix?

Thanks.