Malayalam Font Rendering Issue

I use Qt to develop a writing app. One our our users complained that his Malayalam text is not rendering properly in the latest version of our app, which uses Qt 5.15.17. But it was working before. So, I ran a test and confirmed that it is in fact true.

It's not rendering properly on Qt 5.15.16 and 5.15.17, but it was okay in Qt 5.15.14 and looks like it would render fine in Qt 6.7.1 also.

Also, it appears that this is an issue only on MacOS. On Windows it works fine.

Below is the code

Window {
    width: 320
    height: 240
    visible: true
    title: qsTr("Qt Version ") + Qt.application.version

    Text {
        anchors.centerIn: parent

        font.pointSize: 32
        text: "ചിത്രങ്ങൾ\nശ്രീനിവാസൻ\nഅല്ല\nഡ്രസ്സ്"
    }
}

And this is a sample Malayalam text:

ചിത്രങ്ങൾ
ശ്രീനിവാസൻ
അല്ല
ഡ്രസ്സ്