yup exact same issues on the cube 5x. seems to be a pretty common trait. for mine its only the bottom left corner that seems to lift but strangely when you push it back in it holds and then comes out in another few days.
and the buzzing sound happens as well. seems to be something to do with the cpu because on the right side its totally silent (where the battery is). I read somewhere that it may be the thermal framework in action (since its fanless). did do a bios upgrade but its still there so its probably the hardware build.