I have been facing this issue since a few weeks on testing. For many weeks, it prevented upgrading dbus to the latest version that trickled to Testing. Having manually force-installed dbus via the Recovery Mode's shell, I then ran into this issue:
This is a nasty one, since it also prevents performing a clean poweroff. That systemd-journald line about getting a timeout while attempting to connect to the Watchdog keeps on showing ad infinitum.
What am I missing?