[Samba] winbind passwords expiring

[Chris Smith]

With samba-3.0.23d and an NT4 PDC, passwords expire for no obvious reason when 
using winbind for system services such as ssh(sftp). The users have no 
problem when accessing the Samba shares or logging onto the domain locally, 
but periodically windbind will expire their passwords when attempting to use 
such 'nix services.

Any clues?

Thanks,

Chris