It was worse for me when i hit 8.1, had some problems with scrolling before.
But after 8.1 update, i got phantom presses all the time, turn on display and phone just went nuts and started playing music, going into IE, back, Cortana, homescreen and the it stopped.
Just opening random apps and doing all kind of crazy things.
Did a hard reset and is now back to some issues, but and here is the good part.
I did not have WiFi during the hard reset and therefor i did not get the Nokia software and under that time it worked 100% correct.... flawless!
After i connected to WiFi and got the Nokia "extras" and stuff the scrolling nightmare was back the sec the programs was installed, wtf is this!?
Worked fine worked fine "program has installed", 1ms of freeze and then a press instead of a scroll.
Its like the software is clogging up the systems way of feeling the digitizers response and when it comes back it registers the scroll as a press.
Damn it Nokia!
Edit: I turned on glance and the problem is mostly gone, 1 time in 18hrs.