Exim has stopped using SpamAssassin

[Mike Clarke]

I've just noticed that for the last month Exim does not appear to have been using SpamAssassin to check incoming emails.

Previously all my incoming emails contained the following headers:

X-SA-Exim-Connect-IP:
X-SA-Exim-Mail-From:
X-Spam-Checker-Version: 
X-Spam-Level: 
X-Spam-Status:

But I'm not seeing any of them now.

I've compared things with a ZFS snapshot from a time when it was working and both Exim and SpamAssassin are the same versions as before and there has 
been no changes in /usr/local/etc/exim/configure or /usr/local/etc/exim/sa-exim.conf.

Current versions are:
FreeBSD curlew.lan 9.1-RELEASE-p4 FreeBSD 9.1-RELEASE-p4 #0: Mon Jun 17 11:42:37 UTC 2013     root at amd64 
builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  amd64
exim-sa-exim-4.80.1+4.2_2
p5-Mail-SpamAssassin-3.3.2_8
perl-5.14.4 (was 5.14.2_3 when SpamAssassin was working)

I've re-installed Exim and SpamAssassin using the same make options as before to see if that had any effect but still no joy.

I've set SAEximDebug to 1 in sa-exim.conf but there's still nothing in the logs to help.

Any suggestions where I should look next?

-- 
Mike Clarke