Pushing on the screen can cause black spots to appear on the screen

I head this I called pressure damage.

I have seen the same spots on devices that have had a bad screen replacement. Is this due to the screen being replaced or the low quality screen that it's been replaced with.

I can only discribe the spots as being very similar to the reaction of your finger when you push on the screen of an desktop monitor which uses plastic instead glass to protect the screen.

Thx