From the Google Forums:

Since launch, we’ve also received reports of suspected issues related to the Pixel 2 XL display. We take these reports very seriously and wanted to provide an update. First, there’s been some feedback about the Pixel 2 XL displays not appearing as vibrant as other phones, and in the past few days, there have been a small number of reports of differential aging (also referred to as “burn-in”) on the Pixel 2 XL’s pOLED screen.

And:

Regarding differential aging, we put all of our products through extensive quality assurance before launch and in the manufacturing of every unit. Thorough testing of the Pixel 2 XL display shows that its decay characteristics are similar to OLED panels used in comparable products. Our current investigation of burn-in, which started as soon as we received the first user report on October 22, confirms that the differential aging is in line with that of other premium smartphones and should not affect the normal, day-to-day user experience of the Pixel 2 XL. Regardless, we use software to safeguard the user experience and maximize the life of the OLED display, and we’ll make ongoing software updates to optimize further.

And:

We’re very confident that the Pixel 2 delivers an exceptional smartphone experience, and to give users peace of mind, every Pixel 2 and Pixel 2 XL will now come with a 2-year warranty worldwide.

Hard to know how to react to this. The way I read it, the burn-in is being sold as normal, nothing to see here, move along. If this is the case, there should be reports of burn-in on all OLED displays, no?

As to the Pixel 2 color issues, there’s a detailed explanation in this Google Forums post. It focuses on the Pixel 2 XL using wide Display P3 color gamut, white point temperature settings, and old school sRGB being translated into that space.

Lots to process, props to Google for doubling the warranty.