Simpler reproducer without cloud-init: Add "ExecStartPre=/bin/sleep 1000" to /lib/systemd/system/dbus.service. This happens if dbus.socket is already running, but dbus.service isn't yet as it's blocked by cloud-init.service.
Simpler reproducer without cloud-init: Add "ExecStartPre= /bin/sleep 1000" to /lib/systemd/ system/ dbus.service. This happens if dbus.socket is already running, but dbus.service isn't yet as it's blocked by cloud-init.service.