5c Ghost Touch Issue

I have a 5c that has a mind of it's own... sometimes. From the home screen, if I hover over an icon, close but not touching the screen, an app will activate.

This happens sporadically. Sometimes it will be fine and function normally and then, without reason, it will start randomly activating apps, bring up the keyboard and type, without touching the screen.

It appears that when it freaks out only one area of the touch screen is affected. So when I touch the upper left of the screen it seems to activate whatever is in the middle/lower right. And then without warning, everything works fine for awhile till it happens again.

I've tried 2 new screens and have the same issue. It has been fully restored and updated through iTunes and nothing changed.

I assume it is a hardware/logic board issue but not sure where to start looking.

Any ideas?

Thanks!

Brian