Comment 16 for bug 1384437

The problem is Ubuntu using different versions of gnome at the same time:
gnome-bluetooth 3.8.2.1-0ubuntu9
gnome-settings-daemon 3.12.2-1ubuntu2

or to be more precise: gnome-bluetooth is too old to communicate with gnome-settings-daemon.

Bastien Nocera from the gnome team quickly found the issue:
> Get the distribution to fix this. GNOME 3.12 (when both g-s-d and
> gnome-bluetooth 3.12 are used) will talk to rfkill directly to fix such
> problems. Your mismatched version won't (older gnome-bluetooth doesn't know how
> to talk to the newer gnome-settings-daemon).