Android A11Y TalkBack: Slider does not announce value on change

Context

QtQuick Controls 2 Slider on Android Phone with TalkBack activated to fulfill requirements of WCAG 2.0 / WCAG2ICT

Expectations

• Value should be announced by TalkBack on value change by gesture

Observation

• Changing the value does not announce the value.
• Sometimes the value is announced with wrong/no rounding of the value.

See attached videos

Code

import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.15
import QtQuick.Layouts 1.15

Window {
    visible: true

    Column {

        Slider {
            value: 5
            from: 0
            to: 20
            stepSize: 1
        }

        Button {
            text: "Foo"
        }

    }
}