I’ve run across this issue twice now. I can’t remember how I did it the first time, but I’ve been able to reproduce this issue the second time.
I have the Greek Classical keyboard installed, but whenever I try to type Umineko no naku koro ni into Microsoft Word 2016, without any of my inputs, the keyboard will change to the Greek Classical, and Umineko no naku koro ni changes to Θμινεκο νο νακθ κορο νι. I’m pretty sure this is because I’m typing a foreign name using a Latin script, and none of my other keyboards match, but I don’t understand why it is automatically changing. It isn’t Word since I’ve typed that phrase numerous times before I installed Keyman.