According to the news from Macrumors, they obtained a document from Apple to an Apple licensed service provider, which pointed out the existence of mobile phone screens of some iPhone 12 series (including iPhone 12, iPhone 12 Pro, iPhone 12 Pro Max and iPhone 12 mini) "Greenish" or "grey" issues. Apple is investigating the issue and requires service providers not to replace iPhones for users with this issue, just tell them to update to the latest iOS version.
I believe that Apple’s explanation means that the iPhone 12 series screen color cast problem may be resolved through an iOS update. In June of this year, some iPhone 11 and 11 Pro users experienced the problem of the screen turning green after upgrading to iOS 13.4.1 or later . At that time, some iPhone X/XS users also expressed that they had such problems.
Earlier, the well-known screen evaluation website DisplayMate conducted a display evaluation on the iPhone 12 Pro Max , and found that the machine performed quite well in many aspects, and set a record for the performance of several smart phone displays.