Not sure whether this is exactly the same thing...
Since I did a full reinstall of my desktop to Win11 24H2, my USB DAC (Audioengine D3) goes to sleep after 20-25sec of silence, but turns on again after roughly 5sec of audio. I don't need to reboot.
I hear a 'click' in my PC case when USB goes off & on. Like the sound of a relay or something.
Hope to see a fix for it soon, cause it's annoying!
A fix is coming, it will be tested in the newest insider Preview
Meanwhile you could temp. fix the Problem with this tool: https://veg.by/en/projects/soundkeeper/ (unhearable sound so your sound device will not go to sleep. (but also not your Computer)