High CPU usage with animations on macOS desktop and iOS

Qt applications have a lot of CPU usage on macOS and iOS when playing simple animations.

Consider this demo app:

import QtQuick

Window {
  width: 640
  height: 480
  visible: true
  title: qsTr("Animation test")

  Rectangle {
    width: 100
    height: 100
    anchors.centerIn: parent
    color: "red"
    visible: true

    PropertyAnimation on rotation {
      from: 0
      to: 360
      duration: 1000
      loops: Animation.Infinite
      running: true
    }
  }
}

Gets about 10%+ CPU usage on macOS and 20%+ when running in iOS simulator. More complex apps have even more CPU load until it becomes too much and UI starts lagging.

I would expect something this simple to have <1% usage instead. This is the case on other platforms (tested Windows desktop and Android).

Note: the CPU usage goes away if the animation is not running, or if the application window is not visible (eg. behind other windows). It does not go away if the Rectangle is set to visible: false however.