PHPhotoLibrary addOnly privacy prompt not displayed

I am using the following code to prompt PhotoLibrary access with add only prompt:
PHPhotoLibrary.requestAuthorization(for: .addOnly) { status in
handler(status)
}
However, this still shows the wrong prompt "App would Like to Access Your Photos". Why is that and what can I do to show "App would like to Add to Your Photos" as shown in WWDC video?