I have followed this excellent post to configure Kerberos + LDAP:
http://koo.fi/blog/2013/01/06/ubuntu-12-04-active-directory-authentication/

However, there are some local users used for services.
When I try to change the password for one of those, as root, it asks for Current Kerberos password then exits:

passwd service1
Current Kerberos password:  (I hit enter)
Current Kerberos password:  (I hit enter)
passwd: Authentication token manipulation error
passwd: password unchanged

If I switch to the local user and do passwd, it asks once for Kerberos then falls back to local:
$ passwd
Current Kerberos password:
Changing password for service1.
(current) UNIX password:

My configuration is similar to the site I posted above, and everything works fine, I just can't change the local users' passwords as root.

Thanks in advance for any help.

3.8.0-29-generic #42~precise1-Ubuntu

Update 1 2013-01-31:

# cat /etc/pam.d/common-auth
auth    [success=3 default=ignore]      pam_krb5.so minimum_uid=1000
auth    [success=2 default=ignore]      pam_unix.so nullok_secure try_first_pass
auth    [success=1 default=ignore]      pam_ldap.so use_first_pass
auth    requisite                       pam_deny.so
auth    required                        pam_permit.so
auth    optional                        pam_cap.so


# cat /etc/pam.d/common-password
password        [success=3 default=ignore]      pam_krb5.so minimum_uid=1000
password        [success=2 default=ignore]      pam_unix.so obscure use_authtok try_first_pass sha512
password        [success=1 user_unknown=ignore default=die]     pam_ldap.so use_authtok try_first_pass
password        requisite                       pam_deny.so
password        required                        pam_permit.so
password        optional        pam_gnome_keyring.so