After upgrading to Jenkins ver. 1.504 I cannot login anymore with the
following browsers:

• Chrome
• Chromium
• Opera

Actually I just get redirected back to jenkins/login?from=%2Fjenkins When I enter a wrong username/password then the usual error appears

the only browser where all just works fine is:

• Firefox

I'm not sure it might be an apache proxy issue. However I just post my vhost as well:

https://gist.github.com/anonymous/5099192

UPDATE: I tried to access the Jenkins application directly via http://ci.example.com:8080/jenkins
This shows the same behaviour as described above. So it is not a Httpd proxy issue but most likely a Jenkins bug.