Google is "actively investigating" burn in issues that have started to crop up on some user's Pixel 2 XLs. The latest report follows mixed reviews about the device's LG-sourced pOLED display, which some have said is unworthy of a high-end device priced as it is.
https://www.notebookcheck.net/Pixel-2-XL-screen-prone-to-burn-in.259464.0.html