I have a very similiar problem with a very easy temporary fix (fix lasts about 1 to 30 minutes) and it is hit the back of the chromebook with a medium ish force (but don't go overboard for obvious reasons) under the mouse pad on each side once or twice. I find it helps some. One of my friends replaced the miniature leaf spring ish thing under the mouse pad and the issue went away but that was pretty difficult without proper tools and he cracked the mouse pad in 5 places and dented in 3 places, so it is kind of sharp and not very pleasant to use so I don't recommend that method.