Setting both, MonitorModel.running and FrameTimer.running to true breaks frame timer.

                            model: MonitorModel {
                                id: monitorModel2
                                running: true
                                maximumCount: 20
                                // Just put a FrameTimer inside a MonitorModel and you can use it as a data source
                                // There's no need to set its running property as the MonitorModel will take care of asking
                                // it to update itself when appropriate.
                                // FrameTimer will calculate the frame rate numbers for the given window
                                FrameTimer {
                                    id: frameTimer
                                    // no sense in trying to update the FrameTimer while the window has no surface (or has just an empty one)
                                    running: window && window.contentState === WindowObject.SurfaceWithContent
                                    window: model.window
                                    onAverageFpsChanged: {
                                        console.warn (frameTimer.averageFps)
//                                        console.warn (model.averageFps)

//                                        fpsOverlay.averageFps = frameTimer.averageFps
                                    }

//                                    Component.onCompleted: {
//                                        fpsOverlay.averageFps = Qt.binding(function(){return frameTimer.averageFps})
//                                    }

                                }

                            }

[WARN | qml] 25.01580999191489                                                                                                                           [main.qml:340]
[WARN | qml] 0                                                                                                                                           [main.qml:340]
[WARN | qml] 24.982362452108813                                                                                                                          [main.qml:340]