Display looses pressurepoint after ten seconds what to do?

Hi Folks,

unfortunatly i broke the display on my IPad Air. Everything still worked fine.

I gave the Pad into service to replace the digitizer (glasfront). After i got it back the lowerleft corner cant hold the pressurepoint for more the 10-12 seconds.

This is extremly frustrating while use carrace apps or playing Wot blitz. I tried to rotate the pad but the problem is still there.

Any clues what to do? What the problem could be?

Thx for your help