libpam-ccreds recognizes cached password but cannot login

[Darragh Bailey]

Firstly, I'm not entire certain this bug is in libpam-ccreds, as it may be approving the login and another component is failing to continue. But it seems like a reasonable starting point since installing and enabling cached credentials isn't working as expected.

Description: Ubuntu 16.04 LTS
Release: 16.04

apt-cache policy libpam-ccreds
libpam-ccreds:
  Installed: 10-6build1
  Candidate: 10-6build1
  Version table:
 *** 10-6build1 500
        500 http://ie.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
        100 /var/lib/dpkg/status

I've configure my workstation to authenticate against the corporate active directory, using kerberos and winbind. Additionally I've enabled "cached credentials password saving" and "cached credentials password checking" via pam-auth-update.

Expected behaviour

After boot up
Graphical login greeter appears
Use Active Directory username and password
System determines domain controller is not yet reachable to authenticate
Checks cached credentials
Password matches and message appears "You have been logged on using cached credentials"
Button "Log in" appears
Click "Log in" to continue and desktop appears

Actual behaviour

After boot up
Graphical login greeter appears
Use Active Directory username and password
System determines domain controller is not yet reachable to authenticate
Checks cached credentials
Password matches and message appears "You have been logged on using cached credentials"
Text box asking for username appears and cannot continue. (see attached picture)
Wait 1 minute and retry username and password
Login succeeds as now able to auth against remote server
Desktop appears