Mirror of EKEvent does not show the data

For my EVReflection library I came to a case where a Mirror for an EKEvent did not return any information. Even when going to the complete basics a Mirror did not return anything. When you set a breakpoint at the last line, you will see that there is nothing in the Mirror object. Is this a bug or am I missing something?

    let store = EKEventStore()
    let event = EKEvent(eventStore: store)
    event.startDate = Date()
    event.title = "title"
    event.location = "here"
    event.endDate = Date()
    event.notes = "notes"

    let m = Mirror(reflecting: event)
    print("property count = \(m.children.count)")