iPhone screen periodically unresponsive
Solution 1:
This advise is only meant for iPhone 6 and iPhone 6plus. ONLY.
If you experience problems with your screen being unresponsive, you may suffer from a design flaw of iPhone 6 and iPhone 6 plus that is described here.
So this means your phone is probably broken and has to be replaced eventually. But you can try the following for the time being.
This worked for my phone:
Apply some some light pressure to the case as you would pretend to twist or bend your phone. Only apply light pressure. Don't really bend it though. Just apply some pressure and check if the display is reacting again. It worked in my case. You will have to repeat this all the time it does not respond to touch.
Solution 2:
No, not as a general issue across all apps.
Some apps such as for example Safari may be "slow to scroll" (for example web pages that have Javascript scroll handlers that do not declare themselves as never calling preventDefault() can be slow to scroll).
However, if you see this as a general problem across all apps, and you have to powercycle the phone - it sounds that a hardware problem is likely.
If the phone is still under warranty - take the issue to Apple Support. If it is not, you could still try Apple Support.