It seems like you have disabled the “Auto Create Director Camera” option in the Preferences window. Please enable this option since it handles the creation of the Director Camera automatically. The Director group can not be assigned the Main Camera, but rather only a Director Camera which is automatically created for you with that option enabled.
The cutscene director camera is displayed in the HDMI and any head movement is added as an offset to that cutscene director camera. In practise, Unity VR is taking control of the “Render Camera” found under the “Director Camera Root” gameobject only, while any cutscene camera animation is done in the “Director Camera Root” gameobject itself. The VR support has been tested with the built-in Unity VR support only.