using standard frqa test set an neu of <url>/index.html and a policy for <url>/cgi-bin/* and <url>/cgi-bin/?
Enable post data preservation
then press the button Empty Post to show.cgi
Redirected to authn, then after login show.cgi is shown
Redirected to authn, then after login 404 is shown trying to get to the preserved file..
This differs from if you are already logged in in which case no such error is seen
Also no debug logs are shown for this procedure