Same thing here. What I noticed is in the audio mixer, for Oculus Headset Rift S audio, there are two DEOVR applications with volume controls. The audio is shown on the second one. Changing to Alternate Device audio settings makes it work, but it comes through Unity/Oculus audio device and the video is poor performance. Also if you hit the flat menu button where you would select Reset View or Quit Program, the audio works in the headphones but again, it is going to the Unity/Oculus audio device. I think the issue is the extra DEOVR application that has no audio present (the second one does).