Not surprising, Welcome to Asus, Their quality control is some of the worst I have ever seen, A few years back I went through 7 x PG278Q's, The issues ranged from half the screen being dead, Screen flicker, The whole monitor being covered in dirt, 1 monitor stunk of smoke and the whole base was covered in ash along with another monitor legit stinking of faeces. 
Asus do not give a crap as they know they have a large market share when it comes to monitors so get away with extremely sub par service. 
You will lose out but it's worth it to get away from Asus, Get a replacement, If it's ok sell it and get a Dell.