Pixel 2 XL screen blue tint likely caused by poorly applied polarizer
Here is why the Google Pixel 2 XL has that very noticeable blue tint whenever you tilt the phone just slightly: it uses a polarizer that seems to be applied so poorly that it causes this weird screen coloration.
Screen polarizers are generally a great thing: they allow you to see your phone display when you look at it with sunglasses on.
Google even bragged about this as an important feature of the Google Pixel 2 XL display during the official launch event:
"We've integrated a circular polarizer, which lets you enjoy the screen even when you are wearing sunglasses," vice president of Alphabet Mario Queiroz said emphatically.
However, it is the particular screen polarizer of the Pixel 2 XL that seems to be causing the blue tint of the screen. A demonstration shows how the Pixel 2 XL screen compares to that of the iPhone 8 Plus and the original Google Pixel. The iPhone does a much better job with its polarizer, while the original Pixel lacks a polarizer whatsoever.
The solution to such a problem seems to require new hardware, or at least a new application of the polarizer on the Pixel 2 XL and there seems to be no easy way to fix this via a software update only. And even then, we have the ghosting issues...