Touch screen problem after battery replacement

I changed a battery in iPhone 5 and it has been behaving this way since.

Mirror: https://vid.me/3pCA

Any ideas what could be causing it?

I removed the display very carefully, I changed the battery. I checked all connectors to be plugged in correctly. No parts are damaged in any way. The new battery is not an original, but it's good quality with the exact measurements as an original.

This effect does not occur when I'm setting the display back in but it isn't fully seated in the phone yet. From that I assume the display is not at fault here. The effect occurs the moment I fully seat the display in. It happens with stiffer tapping on the screen or when the phone is gripped tightly - as if there is some tension in the display module. I disassembled the phone again, double checked everything and put it back together. Same issue. I took my time putting it back together and made sure to be overly careful. The display fits in the body easily with no force.

Does anyone have an idea? Has anyone encountered this problem?

Thank you for any advice