Is it the case that you tap somewhere and then the tap is not registered until you touch the screen again, same with short swipes, and delayed effects of long swipes? Sometimes my DV8P has these symptoms and they happen quite randomly, mostly while browsing in Edge. I haven't found any fix for them, they just go after some time. What I noticed is that, in my case at least, they never occur after a restart, only after resuming from sleep.