As of today's git master, the Shut Down, Restart, and Log Out actions no longer do anything when accessed from Kickoff, Kicker, or KRunner. The Sleep, Hibernate, Lock, and Switch user actions do still work as expected.
Can I have a log of dbus-monitor --pcap and pressing the button
Created attachment 141280 [details] DBus log
Log shows a message gets sent to org.kde.LogoutPrompt There's no reply. That means the binary failed to load (or crashed before it could register the service). Given it's one reporter with DBus activation and we have a pattern of this causing setup issues I'm closing this. Ping me on IM if you can't spot the issue.
Just checked again, it seems to be working now. Still, the fragility of this system worries me a bit. Setup issue though it may be, I don't like when things randomly break and then start working again...
>I don't like when things randomly break and then start working again... If it helps, logs show that it launched /usr/libexec/ksmserver-logout-greeter