Yes, you're right and I initially thought that too but it's not just the one pair of headphones - the headphone jack essentially seems to have failed on both computers. No device is working on either computer now.
I had some headphones plugged into my primary computer (running seamless) then switched them over to my secondary to listen to something as I'm not sharing audio between computers. Now the audio jack isn't working on either computer. Opening the sound devices, the headphones are showing up as a disconnected device (can't reconnect them) on my secondary only, and they are named with my primary's computer name. I have tried uninstalling, reinstalling and updating the aud