I have no sound output in the rift headphone either in home, or in VR games when I set the output device to Rift Headphones or Audio Mirroring.
Before I was using my own headphones with the rift and that was working fine but I decided I was going to try the rift headphone for the sake of convenience.
I know it's a software issues since I CAN make them them work sometimes by restarting the OVR service and home several times. And also if I set my windows default audio output to the rift headphones and play music for example, the rift headphones works. So, it's definitely not a hardware issue.
Specs: Delidded i7-8086k @ 5.0 GHz all cores, NZXT X52 cooler, 32GB G.Skill 3200MHz, ASRock Z370 Gaming-ITX/ac, Asus GTX 1080 Strix, Corsair SF600 platinum, Samsung 970 EVO M.2 NVMe 1TB, Samgung 850 EVO 500GB + 840 EVO 500GB in raid0, Seagate Ironwolf 10TB, Louqe Ghost S1, Asus PB287Q 3840x2160 @ 60Hz, Samsung SyncMaster 226BW 1680x1050 @ 60Hz. Oculus Rift S.