I haven't noticed this particular behavior on my system, but have also read of a few others having this problem.
One thing to keep in mind is that Windows is an event-driven operating system, so when you interact with the computer, it triggers a response to your action. The software examines your trigger and then looks up what action or actions that need to be performed in response. I have noticed on numerous occasions that Windows doesn't always follow through on secondary actions if you get to pushing buttons for too short of a duration.
For example, sometimes if you click in a text box in a window, that window gets focus, so you know that the machine saw your mouse click or touch, but the cursor doesn't appear in the box. This can happen because of the machine's reaction time. By the time it finishes giving the Window focus, it may then call another routine that retrieves the actual position of the cursor when the button is clicked only to find that the button is no longer clicked, and thus the cursor doesn't get placed inside the text box.
I don't know if you've tried this or not, and it may or may not help, but when you touch the capacitive start button, try to let your finger linger on it a bit longer and see if that helps the situation.