[exim] $spam_score_int set during sender verification?

Hi,

I could use some clarification on the following issue. In my RCPT ACL, I
have:

deny    message         = Sender verification failed
        !verify         = sender

My first router is this:

bounce_spam:
        driver                  = redirect
        domains                 = !+spam_domains
        allow_fail
        condition               = ${if >{$spam_score_int}{65}{1}{0}}
        data                    = :fail: This message was classified as SPAM
        repeat_use              = false

This router bounces SPAM that was not stopped at SMTP time as a result
of per-domain filtering settings.

Now, today, some messages were refused with the following messages:

550-Verification failed for <masg44klim@???>
550-This message was classified as SPAM
550 Sender verification failed

This indicates that routing during sender verification failed in the
router mentioned above. My question: how could this happen? How could
the $spam_score_int condition ever be true at this time, before any data
is received and the 'spam' condition has not yet run?

Now, I added 'verify = false' the router to prevent failure during
verification, I hope this is sufficient.

Best regards,

Martijn Grendelman