Comment # 7 on bug 1171115 from Matthias Gerstner

(In reply to fabian@ritter-vogt.de from comment #6)
> Can you run "killall polkit-kde-authentication-agent-1;
> /usr/lib64/libexec/polkit-kde-authentication-agent-1 &; disown" before
> attempting a shut down? That should not get killed early and confirm the
> theory.

It does get killed. However I can't tell whether is getting killed "too
early".

Actually nothing should be killed, before the action is authorized. If the
authorization fails then there is nothing to shutdown or reboot.