It's an intermittent issue but very frequent and annoying, and I think it is related to the firefox's over sensitivity to touch pad gestures. I have experienced many times whenever I intend to do a two finger scroll, the browser interprets it as adjusting zoom(which is via two finger pinch). It can't be the issue of my touchpad device / driver issue because pinch zoom and two finger scroll has worked perfectly on other browsers and apps. I haven't encountered a single case where an app interpreted my two finger scroll as a zoom action since the moment i bought this laptop. I believe it has something to do with firefox.