[aclug-L] Password of wrong user got changed

["Bates, Rod" <Rod.Bates@xxxxxxxxxxxxxxxxxx>]

Can anybody explain what happened here? (This is Red Hat 5.2)

I logged on using my ordinary user name, typed "startx", and
went to work.  Many days later, I changed my password in
an xterm window.  I also went to a different xterm where I
had logged on as root, using "su" and changed the root
password.  

At the end of the day, I used lock screen.  Next day, I couldn't
unlock it.  I tried lots of things, eventually trying the new _root_
password, which got me in.  

So does typing "passwd" in an xterm  that is root change the
password of the user the xterm first came up in?  What is going
on here?