REG [5.15 → 6.x]: With `height: implicitHeight` binding changes to implicitHeight won't trigger property interceptor (e.g. Behavior + Animation)

As demonstrated in the following example, explicitly binding height to implicitHeight won't trigger an animation through property interceptor (Behavior) on height. Same with width and implicitWidth. This works (i.e. animates) in Qt 5.15, but not in Qt 6.5.

import QtQuick 2.15

Item {
    width: 300
    height: 300

    Rectangle {
        id: r1

        // set binding at runtime
        height: undefined

        implicitHeight: 30
        implicitWidth: 30

        color: "#2BAE61"

        Behavior on height {
            NumberAnimation {
                duration: 2000
            }
        }
    }

    Component.onCompleted: {
        r1.height = Qt.binding(() => r1.implicitHeight);
        r1.implicitHeight = 60;
    }
}

Bigger snippets with more options to compare Qt 5 & 6 behavior is available at https://invent.kde.org/frameworks/kirigami/-/snippets/2717

Further investigation shows that the bug depends on which expression was bound to the height property at compile time. If it was undefined, then it won't animate; but it was bound to implicitHeight or omitted, then it would animate. Of course, same goes for width.

Not sure which component is to blame here. Also, while binding to implicitHeight is a regression, neither Qt 5 or 6 ever animated/intercepted property changes for undefined/reset height, which severely limits our animating capabilities.