sudo from use with nfs home directory with locked-down permissions

User brisbane has an nfs home directory and is in the admin group.

if the nfs home directory is locked down so that 'other' gets permission denied when cd/listing it, sudo fails, and keeps asking me to type a password.
root@pplxdt08:/home/brisbane# ll -ld
ls: cannot access .: Permission denied

if the nfs home directory is read and executable (listable) to 'other', sudo is successful

I suspect the setud binary "sudo" expects to have acess to the ".sudo_as_admin_successful" file, cannot see it as it does not have permission, and sudo throws an error. I have not verified this as dont know how.

I am using nfsv4 with kerberos, Ubuntu precise fully updated:
Description: Ubuntu 12.04.2 LTS
Release: 12.04
sudo 1.8.3p1-1ubuntu3.4 & sudo-ldap 1.8.3p1-1ubuntu3.4

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: sudo 1.8.3p1-1ubuntu3.4
ProcVersionSignature: Ubuntu 3.2.0-39.62-generic 3.2.39
Uname: Linux 3.2.0-39-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.1
Architecture: amd64
Date: Wed Mar 20 14:39:20 2013
MarkForUpload: True
ProcEnviron:
 LANGUAGE=en_GB:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: sudo
UpgradeStatus: No upgrade log present (probably fresh install)
VisudoCheck:
 visudo: Warning: unused Cmnd_Alias NETWORKING
 /etc/sudoers: parsed OK
mtime.conffile..etc.pam.d.sudo: 2013-03-20T14:37:35.787247
mtime.conffile..etc.sudoers: 2012-06-01T16:09:46.929191
mtime.conffile..etc.sudoers.d.README: 2012-06-01T16:09:47.041191