In January update to Android 8.1 dedicated to Google Pixel 2 and Google Pixel 2 XL caused some problems with unlocking of the phone. New update, which in practice was described as update of security in phone caused other problems, at least for some owners of Google Pixel 2. After downloading new update some people found their devices overheating and many people have problems with shorter life of battery.
One of the Pixel 2 owners informed that his phone warms up to 45 degrees Celsius, and factory reset haven't solved his problem. After turning on battery saver mode phone gets a bit cooler, but battery still isn't working like before the update. People are frustrated, but all they can to do is wait. For now Google even haven't released any official statement connected with this problem.