Try to tighten the display a bit more. But be careful to not tighten it too hard - it could maybe break your faceplate a bit.
I selfmade a dislpay and had a similar problem with a button. You could try to find out where exactly the button sticks. Then you could unsrcrew the faceplate move the transparent display-plate a bit to avoid sticking and then remount the faceplate again. This should help.

TeeMcBee
Got my Mk2! # 080000143