How to Use Quick Notes Using SwiftUI

I am trying to implement Quick Notes through SwiftUI, rather than UIKit or AppKit. I am unsure if the behaviour below is expected, or due to a bug.

I have already successfully implemented NSUserActivity for Handoff, Spotlight and Siri Reminders, using the .userActivity() view modifier. These NSUserActivity instances use the NSUserActivity.userInfo dictionary to store and correctly restore the content through the .onContinueUserActivity(perform: ) methods.

Quick Notes requires using the .persistentIdentifier or .targetContentIdentifier properties, rather than the .userInfo dictionary alone. However, when I set these either of these to unique identifiers using the code below, they are not correctly stored within the useractivity.

MyView()
    .userActivity(ActivityString, updateUserActivity)

private func updateUserActivity(_ activity: NSUserActivity) {
    activity.isEligibleForSearch = true
    activity.isEligibleForHandoff = true
    activity.title = "Title"

    activity.targetContentIdentifier = myItemUniqueID
    activity.persistentIdentifier = myItemUniqueID
    activity.userInfo = ["id": myItemUniqueID]

    print(activity.targetContentIdentifier) // Correctly prints
    print(activity.persistentIdentifier) // Correctly prints
    print(activity.userInfo) // Correctly prints
    }

The identifiers print correctly when setting the user activity above. However, when restoring the user activity (tested through Handoff and Spotlight Search), the targetContentIdentifier and persistentIdentifier strings are empty.

MyView()
    .onContinueUserActivity(ActivityString, perform: continueUserActivity)

private func continueUserActivity(_ activity: NSUserActivity) {

    print(activity.persistentIdentifier) // Nil
    print(activity.targetContentIdentifier) // Nil
    print(activity.userInfo) // Correctly prints
    }

Is there something else I must do, or is this unexpected behaviour?