MailScanner causes SpamAssassin rules to firing inconsistently

[Wolfgang Baudler]

> We run MailScanner 4.85.2 with SpamAssassin 3.4.1 on RHEL6. Bayes and
> Autolearn are disabled.
>
> I tried to add a custom rule to SpamAssassin local.cf and found that it
> fires inconsistently. A simple example rule is
>
> body    TEST_RULE_AA            /SOMETEXT/
> score   TEST_RULE_AA            0.5
>
> If I send a test email locally with the string "SOMETEXT" the rule
> triggers all the time. If I run SpamAssassin from the command line, the
> rule triggers as well
>
> $ spamassassin <test.msg
>
> If I send a test message from an external provider like yahoo however the
> rule does not always fire (some other rules like FREEMAIL_FROM do fire).
>
> The peculiar thing is that they do fire some times if I resend the message
> often enough. I can not figure out what is causing these inconsistencies.
>
> This is a very basic body rule, which should fire unconditionally all the
> time it finds the string. It only has one score, so SpamAssassin score set
> changes shouldn't play into this either.
>
> What am I missing? Why are the rules not applied consistently for every
> email when SpamAssassin is run through MailScanner (and ONLY when it is
> run through MailScanner, sapmassassin detects it 100% of the time when run
> manually)?
>
> Any suggestions appreciated.
>
> Wolfgang
>
>

An additional data point is that this problem is not new to the latest
versions of MailScanner and SpamAssassin. It also occurs with
mailscanner-4.84.6 and spamassassin-3.4.0. I have not tested with other
versions.

Wolfgang