The spam filter is flagging all emails sent to an address that equals the sending address from the same machine as spam bypassing the whitelist. Otherwise can't send yourself an email from same machine. If you click exclude or whitelist in the spam folder, it prompts error message saying the address all ready exists in the list. Seems the whitelist is not being processed before another check is done. From self To self works when the client pulled from another machine. So if you sent yourself an email but keep email on the server, if you check that email from another machine the email is not treated as spam. It appears to be the ESS filter causing this, not the email client or server flagging it as spam. Have not seen any advanced options that would prevent this from happening but the whitelist/excluded address should trump the other checks first anyway.