If "Kerio Anti-spam Processing" debug messages are enabled, your Connect instance is licensed to use the Kerio Anti-spam extension, and spam rating and Kerio Anti-spam is enabled in the Spam Filter settings, you should see either that incoming mail is processed with Kerio Anti-spam, e.g.
[06/May/2016 12:04:44][5828] {kerioantispam} Kerio Anti-spam scans message 'C:\Program Files\Kerio\MailServer\store/queue/1d/572c6c10-00000000.eml'.
or you should see repeated attempts to download files that are required to access the anti-spam service (see this message for more details).