Dell Wyse USB Audio Monitoring

Hello community, out company recently purchased some used Dell Wyse 5070 Thin Clients. We have a very weird problem that happens when user plugs in USB headphones (happens on every model eg. Logitech 960) he can hear himself through the headphones. Seems like some Microphone monitoring is turned on in the ThinsOS. We use ThinOS 9. This problem happens even before user is connected to the VDI.