I have found that if you (accidentally) select a video clip on the timeline (by clicking on it using left mouse button) to select where you want the voice over to begin, BEFORE selecting Record/Capture Option button then selecting Voice Over button and then clicking the START button even though it displays 'press [ESC] or [space] to stop recording' pressing EITHER ESC or SPACE has NO EFFECT. The only way to stop recording is to click on the timeline or any of the tracks.
This is MOST annoying and surely a BUG as why would you want the recording to continue regardless of pressing ESC or SPACE?