In the latest Office Mac - build 171029, you can no longer enter a letter that requires 2 keystrokes to be inputted.
1) start a new document in Word 171019 Mac or Powerpoint 171019
2) set your keyboard layout to French
3) Try to enter ë ê or û. To do so, you need first to type ¨ or ^ and then the matching letter e or u
Not that Word or PPT does display the accent but refuses to type any letter beyond the accent.
WARNING : this is a critical bug that must be fixed before the Slow delivery is pushed!