I currently run Vive pro (1st model) and it has worked fine with multiple vive supported games. With the headset I have Index knuckles as controllers. The game doesn't start in headset at all and shows up only on main screen with loading loop left on headset.

If I access the Steam library view from SteamVR it says I am not using trackable controllers or something along those lines. This makes me suspect that currently Vive is not supported paired with Index controllers.