I haven't seen any mentions of this so I'm going to guess that it's just a bug. After a large update like a UI or an OS sometimes users have to clear out their partition cache. To clear the partition cache power off the phone, when restarting hold both the volume up and power buttons, when the Samsung splash screen appears, release the power button and hold the volume button until the phone fully boots up. Use the volume buttons to navigate and the power button to make selections. Select clear partition cache, then use the reboot option to restart the phone.
If this doesn't work tell us more about what you're seeing.
Does it matter what you're doing when you see the flickering? Tell us when it happens most, when you're watching YouTube, when you're playing this one game, anytime you look at the phone... when does it happen?
Has the phone suffered a fall, been exposed to moisture, or ever had a repair requiring the back be removed?
Does the phone charge normally? Have you noticed it getting hot during charging?
