Hey! The game uses your default audio output. Its possible that when the game starts your Rift thinks its a VR game and changes the audio output to your Rift. You probably would need to change this manually in the software for your Rift. I found this article here, since I dont own a Rift: https://skarredghost.wordpress.com/2016/09/13/how-to-select-oculus-rift-audio-output-device/