Unlock with FaceID is enabled, but (at random) when trying to use the Bitwarden password manager to autofill some credentials, it asks for my Master Password. So I open up the app to see what’s up, put in my password and then find FaceID toggled off. This happens multiple times a day.
I also have this problem on iPhone 15 iOS 17.6.1. Unlock with Face ID = on, Unlock with PIN code = off. The Unlock with PIN code option resets itself to off randomly after using Browser autofill.