[exim] Strange behavior in router

Hi,

I am encountering strange behaviour in this router. Occasionally for a short period of time, the condition evaluates to true when it shouldn't and outgoing mail is quarantined. acl_m8 in the header of the email is null or empty string when clearly it should be a value. By default the value in the table of acl_m8 is -1, unless there is a limit. I checked the Mysql log. There is no panic. Even so, according to the acl_exiscan, acl_m8 should default to -1 anyway. Any suggestions? (exim 4.50, mysql 4.1.14)

Thanks,
C

# Find sender's maximum email size
LIMIT_OUT = SELECT limit_out FROM users WHERE recipient = '${quote_mysql:$sender_address_local_part}'

acl_exiscan:

        accept  set acl_m8 = ${lookup mysql{LIMIT_OUT}{$value}{-1}}
                hosts = +relay_from_hosts

# Save email over limit out
over_limit:
    driver = accept
    domains = ! +local_domains
    condition = ${if and { \
        { ! def:h_X-NOMAIL-Limit:} \
        { >{$acl_m8}{-1}} \
        { >{$message_size}{$acl_m8}} \
        }{1}{0}}
    headers_add = X-NOMAIL-Limit: $acl_m8
    transport = overlimit_quarantine

----------
Craig Jackson
System Administrator
Abbott, Simses & Kuchler
1360 Post Oak Blvd
Houston, Texas 77056
713-627-9393
cjackson@???