Razer headset wont let my pc go to idle

Hi! I bought razer blackshark v2 and using the usb sound card. I have latest synapse and drivers. But when i go away from the pc it shut down the monitor for a few sec then turn on again? It does that repeated. I unplug the usb sound card and then it works normally? How do i fix this or is this a bug? I have razer monitor 27, huntsman keyboard and deathadder mouse but that works just fine. So this must be a bug? Thanks Regards Robin