samba - Dec 2001 - Samba 2.2 PDC has W2K machines spontaneously "leaving" domain.

Hi, all.  I'm running 2.2.2 as my PDC, and all seems to work fine:
machines get added in no problem, and users can authenticate no problem.
HOWEVER, after an indeterminate period of time, W2K machines "decide"
they
want to leave the domain.  Users who've already logged in from the machine
can still log in with cached info, but their profiles no longer get copied
over, and new users can't log in.  As far as I can tell, no single event
is occuring server-side to cause this, nor has it yet happened to more
than one machine at a time.

I'm confused, and users are getting pissed that they have to reset their
profiles from scratch.  Lastly, the smbpasswd file is unchanged, and
re-starting smbd and nmbd have no effect.

Any help would be greatly appreciated!

Thanks,

Ken D'Ambrosio
Sr. SysAdmin,
Xanoptix, Inc.