iOS 18.4 - iPhone 14 Pro Max - open a photo with a face - click on info button and there is no face icon. Also there is no option to add a name to a face. Restart of iPhone didn’t help. Also this small icon of recognized face that should be on each photo with a face- disappeared from old photos.
For help with photos, please post in the Apple Support Community. The Apple Developer Forums are for questions about APIs and features intended specifically for developers.