[ubuntu] After user logout in 16.04, unity-greeter does not load all indicators

Hello,

Just installed Ubuntu 16.04
It uses lightdm and unity-greeter.

When only one user is logged in (Unity session) and he logs out, the login screen does not look fine:
many indicators shown in dconf for unity-greeter are missing (power, sound, keyboard, ...)

Is it a bug ?

The only thing there is in the top right coer is 'onscreen keyboard' or 'screen reader'.

I have to go to a console (ctrl-alt-F1) and restart lightdm to get the indicators back.

After a machine reboot on the other hand, the login screen has everything.