I have iPhone 6 Plus with iOS 9.2.
A couple days ago I noticed that when I scrolled too slowly or my finger lingered on the screen too long the screen would jitter around and randomly activate whatever controls are native to the app. In Safari it might be bookmarks or back button, in iTunes it might be Radio or random song selection, and so forth. At first it was spooky and then it got very irritating, like when you step into a elevator in a hurry to get up to the 12th floor and a little boy suddenly presses every button on the panel for amusement.
Then sometimes the problem went away. It took some time to find this thread but the key was "third party AC adapter." I am traveling, and just before I saw this problem for the first time I realized I left my adapter at home, so I picked up a USB AC adapter from a gas station. That night I saw the problem. I didn't make the connection until I read these posts. If I just use the iPhone without that adapter, problem gone.
When I get home I will test with Apple's adapter.