MailScanner causes SpamAssassin rules to firing inconsistently

[Wolfgang Baudler]

>
> So if I understand correctly, the intermittent non-firing only occurs
> with mail arriving from external sources.

Yes, this is correct.

> Have you looked at the raw
> message bodies of this mail to see what might be different between ones
> that do and don't trigger the rule?
>

Yes, I have compared the headers of test messages in detail. Didn't see
anything wrong or suspicious in them. In fact they look very similar to
our internal headers.

> Have you run a non-fired message as received manually through
> spamassassin?

Yes, the test rule fires 100% in that case.

>
> Have you looked at the MTA and MailScanner logs to see if there are any
> clues there?
>

Yes, I have looked at those logs a lot. No errors or warnings or anything
else that might indicate what is going on.

Wolfgang