Keyboard filter issue - Kiosk mode

Recently I have started rolling out Optiplex 3000 thin client devices with Windows 10 IOT.
They are registered on our WMS server with Kiosk Mode activated.

Users are now complaining they can't use the 'Esc' key anymore.
Kiosk mode seems to lock down keyboard keys, because when kiosk mode is disabled, the 'Esc' key works.

I am trying to find a way to enable the 'Esc' key, but I can't find any documentation on this behavior or if its possible to unblock certain keys in kiosk mode.

Does anyone know if this is even possible?