Normally this type of issue would happen when audio devices have their internal IDs changed, which is something that can happen due to, among other things, a driver update (even if it's not for that specific device), but only if a non-default device is selected within VoiceAttack itself.
You could try changing the Windows default playback device to a different device, and then back to your headset, then change the "Override Default Playback Device" option to do not override, and see if that made a difference.