temporary or permanent fix dnt know but working for me
since the lg g2 touchscreen problem is random so the solution i am.giving may be permanent or temporary but here's what i have done
first flash the kitkat kdz on ur d802 model of lg g2 do a sce flash because it clears ur phone and.makes it.completely new after that if it solves ur touch problem then its ok if not root ur device using ioroot and then using root explorer go to system then u will get a user folder open it and u will get idc like file.name then open it and then open the touch_dev.idc open it change the touch.screen.pressure=0.004 to 0.001 now save it and restart ur phone now open the dialer and dial 3845#*802# then there u will get a setting option click that setring option now there u will find a option named update touch screen firmware click on it and wait for 16secs now close the dialer and restart ur phone it should solve ur problem now cz it solved mine