The issue of my Nokia 6 can be shown via video. Because I am in Cambodia, I can't describe what happened to it. It is the same as my Lumia 520.
Post a link to the video.
That is a problem commonly referred to as "phantom touch".
It can be caused by physical stress to the body/screen of the phone. Remove the screen protector any protective case and lay the phone screen-down on a flat surface. If the phone wobbles unevenly, then the body/screen of the phone has been slighly bent. This is usually caused by keeping the phone in a tight pants pocket. I had the exact same problem with my Lumia 1520. You can try to gently bend the phone back to normal, but you should contact a Nokia Care Center for a repair: https://www.nokia.com/en_int/phones/support/care-center-locator
If the phone body/screen doesn't appear to be bent, you can perform a full factory data reset to hopefully re-calibrate the screen and purge any bad code. Be sure to back up all of your important files and note your installed apps in case you need to reinstall them manually afterwards.
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