SHELL=/bin/false but user can still log in

Hi List, I have an problem with my SuSe 8.2 installation with all current security patches applied. If I enter /bin/false as login shell in the /etc/passwd the user can still login and gets shell access. After rebooting the system the shell entry in the /etc/passwd is processed correct and a login attempt is closed as you would expect. Other entries like home dir in the passwd are parsed correct. Any ideas? Thanks and regards Daniel