As the problem occurs every time you key the mic, a much simpler explanation popped into my mind: Do you have another program running in the background using the same key? Discord, Steam, Teams, Logitech Webcam software, streaming or recording software... There's tons of apps that either are preinstalled, come through updates or come along with installing new hardware. Windows itself has hundreds of keyboard shortcuts but the single key ones are clearly marked. Those using typing keys require at least one assisting key like the Windows/Flag key, Alt, Ctrl or Shift unless you have enabled Sticky Keys under accessibility features.
Another possibility is that if you have several USB devices plugged in, one of them may act as a keyboard, sort of, and conflict with the actual keyboard. I'm talking about having other than flying gear plugged in. AH can see all of your gaming controllers and potentially have some functions assigned to them. I'm talking about pads, steering wheels etc. here. Only have the required USB devices plugged for any game.
Yet another potential culprit is remaining background processes from other games you've played before starting AH. I've been told about frame rate losses, sound issues and other anomalies from players who have been playing several games during one session without restarting their computers in between. A Restart or shutting down by pressing the Shift button while clicking Shutdown will take care of such. Even more so if you have unplugged/swapped USB controllers.
