ログインkshシェルでchfsが機能しない

kshでchfsコマンドが失敗する理由が見つかりません（Puttyを使用してSSHセッションを開きます）。ただし、シェルでkshまたはksh93を再実行すると機能します。

どんな手がかりがありますか？

# alias|grep chfs
# type chfs
chfs is /usr/sbin/chfs
# /usr/sbin/chfs -a size=+256M /opt
Usage: chfs [-n nodename] [-m newmtpt] [-u mtgrp] [-A {yes|no}] [-t {yes|no}] [-p {ro|rw}] [-a attr1=val1] [-d attr] fsname
# ksh93
# /usr/sbin/chfs -a size=+256M /opt
Filesystem size changed to 4194304
# ksh
# /usr/sbin/chfs -a size=+256M /opt
Filesystem size changed to 4718592
# exit
# exit
# /usr/sbin/chfs -a size=+256M /opt
Usage: chfs [-n nodename] [-m newmtpt] [-u mtgrp] [-A {yes|no}] [-t {yes|no}] [-p {ro|rw}] [-a attr1=val1] [-d attr] fsname
# f root
Login name: root                      In real life: Super User
Directory: /root                        Shell: /usr/bin/ksh
On since Sep 06 05:56:55 on pts/4, 4 minutes 30 seconds Idle Time
    from qlhhubfc
On since Sep 06 06:59:40 on pts/6
    from xxxxxxxxxxxx
No Plan.
# ksh
# /usr/sbin/chfs -a size=+256M /opt
Filesystem size changed to 5242880