Comment 2 for bug 1392187

This looks more like an issue with indicator-session, or at least indicator-session getting confused about which Unity is running.

indicator-session is detecting Unity is running. It assumes then that gnome-session is running and tries to make some DBus calls to it. However, in Unity 8, gnome-session is not running, so the DBus calls fail. The callback checks the response from DBus, sees the failure, and upon failure, always signals to display the logout dialog regardless of what type of session request was done, ie, shutdown or reboot.

Marking indicator-session as affected and will work on some solution.