Have Outlook 2013 clients fully patched that are experiencing issues when sending from an MSG template. Basically, the user opens up the .MSG file, customizes it and sends it. The receiving party will receive a blank email. I've narrowed it down to computer/outlook level as the issue can be replicated with Outlook messages sent through Exchange 2013 and GMAIL servers. This means its not a server side issue if email sent through IMAP GMAIL are broken as well. Disabled AV services and issue still occurs.
Found out that .OFT messages are not affected by this. If I open and save an .MSG as an .OFT, the problem goes away. I need to fix it though as not all my users are savvy enough to know how to convert to OFT. This leads to painful help desk calls where user wasted several hours on big project emails.