Restore patch from 1.20.0-0ubuntu3:
* Add debian/patches/terminate-session.patch: Terminate leftover processes
in greeter session. It can happen that the greeter session does not
properly clean up itself on logout. This causes leaked processes like
settings-daemon which act on the user session as they share the same
$DISPLAY. Ask logind to terminate remaining processes in the greeter
session on closing, which is more robust than trying to fix every greeter.
(LP: #1637758)
-- Martin Pitt <email address hidden> Tue, 22 Nov 2016 09:43:39 +0100
Which suggests that the issue might be lightdm-gtk-greeter being killed before the unlock has completed?
The change in there is:
Restore patch from 1.20.0-0ubuntu3: patches/ terminate- session. patch: Terminate leftover processes
* Add debian/
in greeter session. It can happen that the greeter session does not
properly clean up itself on logout. This causes leaked processes like
settings-daemon which act on the user session as they share the same
$DISPLAY. Ask logind to terminate remaining processes in the greeter
session on closing, which is more robust than trying to fix every greeter.
(LP: #1637758)
-- Martin Pitt <email address hidden> Tue, 22 Nov 2016 09:43:39 +0100
Which suggests that the issue might be lightdm-gtk-greeter being killed before the unlock has completed?