Comment 3 for bug 1336663

Yes. This bug probably means that lightdm is not associating the login session's environment with the pam handle for the unlock action. It looks like lightdm correctly copies the contents of the pam env (pam_getenvlist) to the session environment (judging by the $KRB5CCNAME that I have in my environment here), but evidently it doesn't save this information for later use for the unlock screen, which it needs to do.

A valid way to do this would be to keep the pam handle open for the duration of the login session, and reference it for any unlock actions.