Re: Problem with /etc/security script?

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sun, 7 Oct 2018 07:39:42 +0800 (+08)
    From:        Paul Goyette <paul%whooppee.com@localhost>
    Message-ID:  <Pine.NEB.4.64.1810070738190.1364%speedy.whooppee.com@localhost>

  | I'm just using a normal simple postfix as far as I know.

You could check its config, to see how it delivers mail (but it should be using
mail.local to do that, and invoking it without the -l flag unless your /var/mail
is accessed via NFS.

But it is more likely that the .lock files are coming from some user agent - 
something that is reading mail, and has been configured to use the wrong
kind of locking when fetching mail from /var/mail

kre