After tinkering, I was able to find two numpad keys that work
Keyboard.key_code(223,0); //Numpad3
Keyboard.key_code(225,0); //Numpad9
But couldn’t find anymore codes to work. These codes don’t fit anything in particular? Do not appear to be ascii? 221,222, etc do not trigger any num keys.
Seems this user also ran into problems with BLE Nano 33 which is also mbed board runing same ARM processor.