https://arstechnica.com/gadgets/2018/08/google-pixel-xl-users-say-android-9-pie-causes-quick-charging-problems/

Despite a lengthy beta period that lasted around fives months, it seems Android 9 Pie managed to ship with a few bugs. As first noticed by Android Police, Pixel XL owners are saying that updating to Google's latest mobile OS is causing problems with quick charging.