This bug had been marked as a duplicate of bug #1245295 "Greeter indicates session is logged into after logout" (https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1245295).
However a fix has been released for bug #1245295 (that effectively fixes the bug with the greeter) but the bug described above still occurs from time to time (but not always), so I removed bug #1245295 as a duplicate of this bug.
This bug had been marked as a duplicate of bug #1245295 "Greeter indicates session is logged into after logout" (https:/ /bugs.launchpad .net/ubuntu/ +source/ lightdm/ +bug/1245295).
However a fix has been released for bug #1245295 (that effectively fixes the bug with the greeter) but the bug described above still occurs from time to time (but not always), so I removed bug #1245295 as a duplicate of this bug.