Can't change/expire passwords

[andrew fabbro <afabbro_(_at_)_indoctrination_(_dot_)_com>]

I can't get a user's 'change' or 'expire' time to have any effect on his
login.

I used chpass(1) as root to modify the 'change' field for a password entry:

#Changing user database information for testuser.
Login: testuser
Encrypted password: <snipped for this e-mail>
Uid [#]: 1003
Gid [# or name]: 1003
Change [month day year]: July 01, 2000
Expire [month day year]:
Class:
Home directory: /home/testuser
Shell: /bin/csh
Full Name: test user
Office Location:
Office Phone:
Home Phone:

Sure enough, /etc/passwd shows the change.  Pasting from vipw:

testuser:<snipped>:1003:1003::962438400:0:test user,,,:/home/testuser:/bin/csh

However, when I login as that user, I am not prompted to change my password.
962438400 is Sat Jul  1 01:00:00 PDT 2000.  My system time as I type this
is Thu Jul  6 05:55:53 PDT 2000.  I also tried 1 second instead of 
962438400 by manually vipw-ing.

I have the same experience if I use chpass(1) to change the user's 'expire'
time.  Same if I change both ;)  I am not using Kerberos or NIS.  

What am I missing?

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