Face ID iphone 12 Pro working

Kindly reach out to the Store/Individual/Agency from whom you acquired your iPhone 11. They would be best equipped to confirm whether the device has undergone servicing by an unauthorized service provider.

In case you recall not encountering this message at the time of purchase and it surfaced after an update, it's important to note that this message is visible specifically on iOS 15.2 and subsequent versions. It might be beneficial to inquire about any recent updates or changes made to the device's software configuration that could have triggered this notification.

Understanding the circumstances surrounding the appearance of this message could provide insights into any alterations in the device's service history or software updates that have brought about this notice.

Parts and service history

With iPhone 12 models and later using iOS 15.2 and later, you can go to Settings > General > About to see the parts and service history of your iPhone and you can see if the camera has been replaced. If the repair was done using genuine Apple parts and processes, you will see "Genuine Apple Part" next to Camera.

• You will see an Unknown Part  message if the camera installation is incomplete or if the camera:
• Was replaced with a nongenuine camera
• Was already used or installed in another iPhone
• Isn't functioning as expected

This message doesn't affect your ability to use your iPhone or access your camera.

Learn more about iPhone parts and service history.

The only way to get the notification removed is by replacing the ingenuie parts with a genuine Apple Parts through an Apple Authorised Sercvice Center.

Take your device to an Apple Retail Store or Apple Authorized Service Provider, or contact Apple Support:

Apple Repair and Repair Status Check - Official Apple Support

Apple Authorized Service Provider

Find Locations - Location Selector - Apple

Contact Apple for support and service - Apple Support 

iOS updates generally aim to enhance user experience, boost security, and fix bugs rather than disrupt core features. Face ID issues after updates might stem from underlying, unmentioned factors. Updates won't typically alter personal data but may refine settings or features. Backup before major updates for safety. Review Apple's update details and backup advice for a smooth process.

This seems purely coincidental so please check the Setting on your device.

See what each update does: About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...