The screen flickering occurs under these conditions:
I have tried updating the the display drivers both via device manager and doing the auto search and by attempting manual install with an intel driver from intel's site. Interestingly enough, I have found that when I roll back the display driver via device manager the driver date is some date in April of 2016, but when I update to the latest, the driver date is some date in July of 2015. Very weird. And I am completely unable to manual install with intel's own drivers because "the computer is not validated for this driver, go to the manufacturer's website..." Asus doesn't seem to have any graphics drivers for the UX301LA on their site, either. I should also clarify that the issue persists regardless of which driver I use.
Screen flickering is 100% gone when I disable the Intel Iris 5100 Graphics in device manager.
And when I open the start menu (usually by pressing the windows key) the screen flickering immediately stops.
Anyone else with this problem, not even restricted to the zenbook?
Edit: Solved, apparently updating my BIOS did it. I was having a separate BIOS related issue as well regarding being stuck in a BIOS reboot loop when my laptop awoke from sleep.