After receiving the same email 3 times, Outlook starts sending it to junk


Outlook version
Outlook 2010 64 bit
Email Account
Exchange Server
So I have a form on my website that sends out petitions based on names checked off on the form. Once I receive the petition 3 times, Outlook is starting to junk it. If I change the subject line, it accepts it 3 times again and then starts junking it. On my end I can add it to the safe senders list, but the people receiving the petitions are less likely to do that. Is there some sort of Junk filter that won't allow the same message to hit the inbox? It's only happening in Outlook and So weird.