I love how so many responses in this thread are, "You have to train the voice recognition thingy!" in spite of the OP stating - repeatedly - that this is not a recognition issue. Totally love it. Not.
I get where the OP is coming from. I also run VoiceAttack, or try to. I also run into this issue where the program responds absolutely perfectly for a while, does everything you want it to, when you tell it to, then all of a sudden, out of
nowhere, the program responds to nothing. Zero. Zilch.
This is not related to HCS Voicepacks. Those who run HCS Voicepacks may have the same issue, but it's not the Voicepacks. How do I know? I bought Verity long, long ago - and she's not installed in my current installation of VoiceAttack. I use a 100% custom profile for Elite.
As mentioned, this is not a recognition issue. It just stops listening to anything for a short time - somewhere up to about 20 seconds, by my reckoning, 20 long, frustrating-as-heck seconds, before it's suddenly back, listening to all commands again as perfectly as it did before it freaked out.
There is nothing indicating it's trying to process speech into commands - there's no lag on my system when this occurs (no idea about the OP).
I have another issue with VA as well, significantly more serious, but that issue is beyond the scope of this thread, and I'm not entirely convinced that issue is actually VA, after doing some research...