No sure really but Asus has alway been very dodgy with their warranties in general, not just monitors, and in my experience have always tried to pass blame.
LG burn in warranty seems to be up for debate, multiple tech sites reported that LG decided to include a 2 year burn in warranty last summer but I couldn't find any mention of it on LG's site. Some people claim its just in the US even though UK tech sites reported the change but then I was watching a video review of the LG 27" OLED by an American guy and he rang LG on during the review to ask what the situation was and the customer service rep told him LG don't cover burn in.
So I guess the answer is **** knows