Recently, some iPhone 11/11 Pro users indicated that their iPhone screen turned "green" after unlocking. From the reddit discussion forum, some people said that after upgrading their iOS 11.4.1 or newer version of their iPhone 11 and 11 Pro, the screen had a color change problem and turned green. A small number of iPhone X/XS users also expressed such problems.
Since the iPhone 11/11 Pro uses LCD and OLED screens respectively, the two iPhones with different screen specifications are also experiencing this problem, which means that the problem is probably from the software rather than the hardware.
It is not known under what conditions this Bugs will be launched. I believe that it will not be possible to solve the problem until Apple launches a new version of iOS.