I too am having the same issue.
I use xbox controller with Elite Dangerous and have the game headlook toggle set to right thumbstick press.
I have the Tobii 4c set to enable/disable toggle on CTRL+T.
Pressing CTRL+T does indeed disable the head/eye tracking but It will not enable the manual headlook in game clicking the thumbstick or any other items. So I am stuck with the fixed view!
When it comes to disabling tracking so I can use original game bindings I have to stop all tobii interference before starting the game. Usually by killing processes/services. Turning off within infinite screen does not usually work.
If I start with in game bindings working then I can get Tobii software to take over by starting the tracking software but once it has taken over I can never revert back to normal game key bindings for headlook without a full restart.