I am also having issues with this. The EyeXHost is created in one scene and is itself set to be persistent with Don’t DestroyOnLoad, but when I load a new scene, I lose tracking capability. I also went as far as to try to make my GazePointDataComponent and UserPresenceComponent persist across scene boundaries. I am using Unity 5.3.2p3. Like the previous poster, I realized I could get the tracking back after a scene load if I Alt-Tab out and click back in.