Google has been taking some heat over the LG-manufactured OLED display used on the Pixel 2 XL smartphone, which was shown to suffer from screen burn-in problems, sometimes only with a few hours of use. Google stepped up and stated that this was normal with an OLED screen such as the one used on the smartphone. Apple is heading off future complaints

Source: Hot Hardware – Apple Warns iPhone X Users About OLED Display Burn-In And Off-Angle Color Shifting