Charger outputs "dirty " current that causes interference with touch screen.
Yes matrix can be seen on all devices, something similar can be seen on SE phones when turned off or on black background against sunlight.
Thanks for shining some light on the "issue", I really appreciate it!
I have a friend with xperia s and i can confirm that.
Looks like I'll need a new charger, which kinda bums me out, but other than that, the Blade III is a pretty solid phone so far.