Hi Nathanielmoss,
Sorry for the inconvenience this issue has caused.
From your description, the issue does not exist in Outlook Web App, so it might be caused by the Outlook for Mac client itself.
To troubleshoot the issue, we can remove the account in Outlook client and then rebuild the Outlook for Mac database. Here are the steps:
1. Open Outlook client, navigate to Tools, in the left pane of the Accounts dialog box, select the account, and then click Delete.
2. Rebuild the Outlook for Mac database. Please refer to this article for the detailed steps:
http://support.microsoft.com/kb/2360509
3. Set up email in Outlook for Mac:
Regards,
Robert