The display is not fixed


I bought a used Electra One a few days ago. There’s a little problem with it.
I noticed that if I touch the display a little harder (but not hard!), most of the screen is not stable, because of the lower left corner not fix.
The screen moves “everywhere” (approx. 0,5 mm), but mostly in the lower left corner.
In the other corners, the screen is completely fixed even with such a slightly stronger touch.
When touched, you can see the display moving and hear it “knock”.
What could be the reason for this? Can this be easily fixed?
I have already contacted the manufacturers.
[iCloud](ElectraOne Screen Video)