That's exactly what's happening to me!
There is now way the software is supposed to do that, and no mic is powerful to pick up sound coming from your headphones, unless they were off your head with volume cranked.
Somehow, VA is inadvertently listening to what is coming through the headphones. When I shout, it occasionally recognizes my commands, and when the game is very quiet, it recognizes fine.
I've sent an email, as my forum post has received no replies. If/when the problem is resolved, I will post in this thread or create a new thread.
As it is, VA is unworkable with games.
Henk