Qt 5 kit cannot handle easing curves

Steps to reproduce

1. Launch Qt DS and create a new project that targets Qt 5.15
2. Replace the generated *.ui.qml file with the sample code below and save the changes

import QtQuick 2.15

Rectangle {
    id: rectangle
    width: 640
    height: 480

    Text {
        id: label
        text: "Hello World"
        anchors.centerIn: parent
    }

    PropertyAnimation {
        id: anim
        target: label
        property: "font.pointSize"
        easing.bezierCurve: [0.2, 0.2, 0.8, 0.8, 1, 1]
        running: true
        from: 9
        to: 48
    }
}

Outcomes

• The code model annotates '"easing" does not have members. (M17)' in the Code pane
• The 2D designer becomes unusable

Workaround (only usable on Qt DS 3.9, not on Qt DS 4.0)

Click Tools > QML/JS > Reset Code Model to make the error disappear

Other notes

• Switching to the Qt 6 kit makes the issue go away
• If you comment out the easing.bezierCurve line, Qt DS is happy. Qt DS also lets you can launch the Qt DS Easing Curve Editor (https://doc.qt.io/qtdesignstudio/qtquick-editing-easing-curves.html ) to add a curve to the PropertyAnimation. However, clicking "OK" in the editor will also produce the M17 error, and the easing curve code will not be added.

Original report
 

Preview the QML file error, "much" does not have members. (M17)The correct one is 'easing". Changing to 'Easing' gives you a preview, but it runs incorrectly.