2017 15'' TB MBP. My "B" button occasionally does not work. It will either give a false negative (press button, does not register press); or false positives (press bbutton...there, it just did it...and get more than one press). This happened a month ago and resolved on its own. Now it's back. All other buttons are ok. Any way to remove the individual button cap to inspect it? I don't want a "genius" ripping my laptop apart.