A QAS user whose home directory is NFS mounted can't login when the NFS server is not available.
When the NFS home directory's share is unmounted cleanly, a user can log in and create a home directory under the /home mount point just fine. When /home was nfs mounted and the NFS share on the server was disabled, the workstation was unable to unmount cleanly so users were prevented from logging in.
As a workaround in this rare event, a user could reboot their machine and log in normally. Since the NFS share is no longer available, it will not mount leaving the local /home mount point available for home directory creation/use.