I contacted my email provider to have them empty out the contents of the Junk Mail folder, which they did. But they also told me this duplication is a know issue in Outlook 2013. Wow! That is quite an issue, and there is no fix for it. Here is what you need to do if you use Outlook 2013:
1. Click the “Junk” button to drop down the menu, and choose “Junk E-mail Options”.
2. On the “General” tab, make sure that “No Automatic Filtering” is selected.
3. On the “Blocked Senders” tab, delete every entry from the list of blocked email addresses or domain names.
4. Click “OK” to close the “Junk E-mail Options” pop-up window.
5. Select and delete all messages in the “Junk E-mail” folder.
6. Restart Outlook
Finally, after doing so, be sure not to use the “Junk” button when viewing a message. This button immediately moves the current message into the “Junk E-mail” folder, which can trigger the infinite loop again.
If you need any assistance with this, feel free to contact me.