So is it picking up audio with the button not engaged?
Very possible, my USB microphone led stays on even when the computer powered
is off. I am looking at a desk top computer that is off, and inside there are
led lights on, I can see them through the vent holes.
Leds are Cool.
Your computer may be set to provide USB power when it is 'turned off'. Likewise, even when turned off, indicator lights will probably still be lit inside the case. It's no big deal.
If you wish to test this out, while your computer is 'off', speak into your microphone about your desire for a cheeseburger, or a new Mustang, or (make up something absurd). Then fire it back up a bit later and see if you start getting advertisements for said products.
And finally, if you are really convinced that Big Brother is watching and listening, just set an audio player next to the mic while you're out/asleep/etc playing old episodes of Amos and Andy, (or whatever) on repeat. If nothing else it'll confuse the heck out of them.
If i am not currently using a desktop I will disconnect them from the internet. And they are all old as the hills. lol.
Today Im afraid the old way to be “spy-proof” is get rid of all the devices that connect to the internet or cable systems
And lose all your smart phones in a boating accident.