I am attempting to login to a web application using form based authentication with a custom authenticator. Everything works fine if you type the correct username/pwd. But when you type an incorrect username/pwd, you receive a 403 error page instead of the login failed page as configured in the web.xml. The strange thing is that this did not start occuring until we upgraded to 8.1 SP4. The same code works fine on 8.1 SP3 and lower. Is there a bug with SP4?