Comment #93 fixed it for me; adding "stop on runlevel [06]" to /etc/init/network-manager.conf.
Since this is specific to network-manager / dbus / upstart, I have filed a new bug about it: bug 937866.
Also comment #91 seems to make sense, but I have not checked if it's applied to Ubuntu's kernel already.
Comment #93 fixed it for me; adding "stop on runlevel [06]" to /etc/init/ network- manager. conf.
Since this is specific to network-manager / dbus / upstart, I have filed a new bug about it: bug 937866.
Also comment #91 seems to make sense, but I have not checked if it's applied to Ubuntu's kernel already.
I am using Ubuntu Precise (development release).