Greetings @wheeler,
Yeah Cog is a little strange with they virtual keyboard interaction. One workaround to disable it would be to run Weston with kiosk-shell: Working with Weston on TorizonCore | Toradex Developer Center
Another option would be to modify the weston.ini so that weston-keyboard has a invalid path. For example:
[input-method]
path=/usr/lib/<wrong-path>/weston-keyboard
Best Regards,
Jeremias