camera key bindings ignored

[rayx]

Settings > General > Camera > Camera Left/Right/Up/Down bindings are ignored.
Clearing these bindings, or binding these functions to different keys, does nothing: the default Num 4/6/9/2 remain in control no matter what.
For example,
clear the Camera Left binding (left and right binding slots empty),
then bind Camera Left to the [ key in the left hand binding column ([ in left slot, right slot empty),
go back to game
press [ (nothing happens)
press Num 4 (camera turns left)
This makes it impossible to use the stick controls for cockpit look around.
All other keybindings I have tried (e.g. Roll Left bound to stick button 16) work.