“The iOS 17.1 update that is expected to be released to the public next week does not appear to address an issue that is causing some iPhone models to turn off sporadically at night, interrupting alarms, silencing notifications, and otherwise disrupting nighttime ‌iPhone‌ usage.”

https://www.macrumors.com/2023/10/18/ios-17-1-shutdown-bug-no-fix/