[exim] Forwarding mail onto Junk for no reason

I've been using exim for over a year now with no problems but overnight
exim has started to forward all my mail to my Junk folder.

example from log:
2006-02-17 08:28:59 1FA0z5-0006Ds-0e => /home/cbolton/mail/Junk
<cbolton@???> R=userforward T=address_file

The messages hasn't been marked as spam:

X-Spam-Status: No, score=0.4 required=7.5 tests=AWL,BAYES_00,FORGED_RCVD_HELO,
    HTML_90_100,HTML_MESSAGE,HTML_SHORT_COMMENT,HTML_TITLE_EMPTY,
    MISSING_SUBJECT autolearn=no version=3.1.0

and the only thing in my .forward file that refers to the Junk folder is:

if $h_X-Spam-Status: contains "Yes"
        or
    "${if def:h_X-Spam-Flag {def}{undef}}" is "def"
then
    save $home/mail/Junk
    finish
endif

I decided to use this opportunity to update to version 4.60 (4.54
previous) and its still doing it. Is there something I've missed?

Cheers.
Chris