Problem using secret-tool as root

Ubuntu release: 18.10 x64
Package version: libsecret-tools 0.18.6-3

Command example: sudo secret-tool store --label='password' key value (similar issues can be obtained with secret-tool lookup / clear / search)

Expected behavior: the same behavior as a non-privileged user, that is: no output in stdout nor syslog, secret-tool simply asks for the password and stores it.

Observed behavior: After a few seconds of waiting, secret-tool crashes with the following output in stdout:

(secret-tool:3394): GLib-GObject-CRITICAL **: 15:45:12.811: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
secret-tool: Error calling StartServiceByName for org.freedesktop.secrets: Timeout was reached

and the following output in /var/log/syslog:

dbus-daemon[4246]: [session uid=0 pid=4244] AppArmor D-Bus mediation is enabled
dbus-daemon[4246]: [session uid=0 pid=4244] Activating service name='org.freedesktop.secrets' requested by ':1.0' (uid=0 pid=4240 comm="secret-tool store --label=password key value " label="unconfined")
gnome-keyring-d[4249]: couldn't create socket directory: /home/user/.cache/keyring-XTN8SZ: Permission denied
gnome-keyring-d[4249]: couldn't bind to control socket: /home/user/.cache/keyring-XTN8SZ/control: Permission denied