Automatic forwarding of email from one address to another address or account will result in substantially reduced filtering accuracy, as well as an increased rate of false-positives.
This is because the email server that provides the forwarding becomes an unwitting spam relay (accepts the spam and then delivers it to another address) and also inserts it's own "Received" and "X-Headers" into the email itself. As a result, the forwarded email is no longer exactly the same email as sent by the original sender.
As a consequence, there is even the chance that the forwarding mail server could be blocked by our firewall, resulting in all messages (spam and otherwise) being refused by our server and returned to the original sender as undeliverable.
The best solution for filtering forwarded email is to have OnlyMyEmail filter the actual and original recipient address/mailbox, before any email forwarding occurs.
Regardless, we will still attempt to provide "minimal filtering" when analyzing email that has been forwarded to an address protected by our system. However, we cannot guarantee filtering accuracy and we will not analyze emails for filtering errors in these cases, as such errors are actually a known result caused by forwarding emails from one account/address to another.
