It seems that kcheckpass now tries pam_setcred with PAM_REFRESH_CRED instead of PAM_ESTABLISH_CRED which isn't a bad idea. But unfortunately if the renewal time of your kerberos ticket has expired it will not grab a new ticket for you. I don't know enough about pam but it would be nice (if pam_setcred returns an error) to detect this and retry with PAM_ESTABLISH_CRED so the user always has a valid ticket. Unfortunately #191049 is closed so I have no idea what the reasoning behind the change is.
> Unfortunately #191049 is closed puzzling statement since *this* bug is #191049. (: Did you mean to refer to a different one?
*This* bug is #196587 :) In any case this bug seems to be fixed now, I do get new tickets every time I unlock my screen. I haven't checked what has changed but I can login to my desktop every morning (since my home is nfs4 with kerberos, I do notice right away if I don't have a ticket.)