Almost a year later, grantmo to the rescue!
I used to just ignore this issue but figured I'd spend some time today trying to figure it out. Send to Bluetooth has caused other issues in our organisation in the past, don't know why I didn't disable it earlier!

Does MS create the plug-in or is it made by the BT OEM drivers?

Pity it still manages to cause issues in Office 2013 :/
Here I was thinking it was because the template was on the network. . .