Comment 32 for bug 353278

Yes, you are right! I purged them (with -force-depends in dpkg), install them with apt-get from the official repo, and they are working fine. I didn't reboot, but I logged out and in before testing. I am sure that would clean up anything in memory.

So, it must be something about the order in which the post-install scripts are executed, right? It would be nice to understand exactly what's going on and fix it for good :-)

I hope someone here can try your suggestion to confirm (I'll ask the folks in kubuntuforums.net, too)

sudo apt-get install --reinstall libpolkit-dbus2 libpolkit-grant2 libpolkit2 policykit