Slider component ignores discrete tickmarks when scrolling with a trackpad

Possibly I have posted this bug report to the wrong component. Please let me know.

A slider can be set to use discrete steps which it has to snap to. Using the scroll wheel each 'click' will move the handle to a level above or below. However, when scrolling using the trackpad using two fingers I am able to position the slider in between the discrete values. 

The test case below can be used to reproduce the issue.

import QtQuick 2.6
import QtQuick.Controls 2.15 as QQC2

Item {
    implicitWidth: 500
    implicitHeight: 300

    QQC2.Slider {
        wheelEnabled: true
        snapMode: Slider.SnapAlways
        anchors.centerIn: parent
        from: 1
        stepSize: 1
        to: 10
    }
}

Just position the cursor over the slider and scroll with a touchpad. The handle will move freely, rather than snapping to the tickmarks.