As a minor update, iOS 17.1.2 should be focused on bug fixes, but it’s unclear exactly which issues might be addressed. Some users have continued to experience Wi-Fi issues on iOS 17.1.1, so perhaps iOS 17.1.2 will include the same fix for Wi-Fi connectivity issues that Apple already included in the iOS 17.2 beta. Some users have also experienced minor bugs related to push notifications, HomeKit, and more.
iOS 16.1.2 was released during the week after U.S. Thanksgiving last year, so there is precedent for a bug-fix update being released this week.