Some time our phone auto update software we don't know get some issues example green line or other function not working so please change your phone setting
Go to setting >software update >close auto update & install thanks
or simply use A series that doesn't have Super AMOLED+ just "Super AMOLED", check GSMArena before buy a new phone
because even you don't update your phone, there's a low chance your S, Note, Z, or any Galaxy phone that has Super AMOLED+ screen will suffer green line, hopefully you won't suffer it
i actually did this setting from the start. but the update thing kept popping out. i think it happened when i put my phone in my pocket and the accidental press allowed the installation of updates. of course its super low chance but it does still happen. the update thing pop out every day, and then, until u update. its almost like they forcing you to update
