[ale] bug? passwd changing after su during a telnet session

[Zhongbin Yu " <zyu at tc.net>]

greet all,
(refer to the telnet session appended)
I did a telnet to my linux box as user A, su to root, then su to user B.
Then as user B, I tried to change passwd. I would expect it changes passwd
for B. Instead, it tried to change passwd for A. I actually did change
A's passwd while I am supposed to be B, a peer of A.  Repeat the above
locally on the box without telneting will change passwd for B as expected,
though. I only have one RH5.2 box now so I can't check on other RH5.2 box.
I will check RH6.0 at home.
Normal behavior or bug?

[jerry at punch jerry]$ rpm -aq|grep bash
bash-1.14.7-13
[jerry at punch jerry]$ rpm -aq|grep telnet
telnet-0.10-5
[jerry at punch jerry]$ uname -a
Linux punch.SomeCompany.com 2.2.3 #2 Tue Mar 23 18:28:26 EST 1999 i586 unknown
[jerry at punch jerry]$ ls -l /bin/su
-rwsr-xr-x   1 root     root        12648 Aug  5  1998 /bin/su
[jerry at punch jerry]$ ls -l /usr/bin/passwd
-r-sr-xr-x   1 root     bin         15613 Apr 27  1998 /usr/bin/passwd

Jerry Yu
----------------------------------------------------------------------------
Systems Engineer	| zyu at tc.net
SomeCompany Technologies| 404-262-8544(O)	1-800-979-1105 (P)
Atlanta, GA 30326	| ae.tc.net/dept/engineering/op/public/developer/zyu


billing:/# telnet punch
Trying 11.42.193.132...
Connected to punch.SomeCompany.com.
Escape character is '^]'.

Red Hat Linux release 5.2 (Apollo)
Kernel 2.2.3 on an i586
login: zyu
Password: 
Last login: Wed May 12 14:52:10 from 10.16.208.175
You have new mail.
/home/zyu$ su -
Password: 
punch:/root# id
uid=0(root) gid=0(root)
groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),1
(wheel)
punch:/root# su - jerry
[jerry at punch jerry]$ id  
uid=510(jerry) gid=511(jerry) groups=511(jerry)
[jerry at punch jerry]$ passwd
Changing password for zyu
(current) UNIX password: 

passwd: Conversation error	<this is after a ctrl-D>
[jerry at punch jerry]$ id
uid=510(jerry) gid=511(jerry) groups=511(jerry)
[jerry at punch jerry]$ id -r -u -n
jerry
[jerry at punch jerry]$ 
[jerry at punch jerry]$ passwd
Changing password for zyu
(current) UNIX password: 
New UNIX password: 
Retype new UNIX password: 
passwd: all authentication tokens updated successfully
[jerry at punch jerry]$