It's possible that Tilt is currently mapped to pitch bend. The Tilt Disabled Return Value parameter will not function when Tilt is mapped to pitch bend. It will only function as expected when mapped to a CC.
It is also important to remember that the Tilt Disabled Return Value is only output when Tilt is disabled from the K-Board itself (by holding down the Tilt button for 1 second). The value will not be sent out in any other context.