It looks like the best option for help will be our iCloud Support. From the article is named iCloud: Identifying and filtering spam found here http://support.apple.com/kb/HT4899.
Due to the complexity of accurately detecting and filtering out spam, on rare occasions a legitimate email from a friendly source may be blocked from reaching your Inbox. This is called a false-positive. If you feel that a legitimate email message was inadvertently filtered, you may want to ask your friend to send a follow up email to verify the issue exists before contacting support. If you notice that multiple email messages are being delayed, bounced, or not delivered, please contact iCloud Support directly.
This is frusterating since there is NO way to contact iCloud Support directly unless I have Apple Care or am under the 90 day complimentary support, especially when I'm trying to make Apple aware of a bug on their end...
Furthermore, the way Apple describes junk mail filtering and the way it's supposed to work does not match up with reality. Case in point, Apple explains that when you mark a message as either junk or not junk - that sender will be added to a list to prevent future falso postives/negatives.
Not sure where to go from here as I'm out of options...