The issue occurs with the attached "Montserrat" font in a basic QML code:

    FontLoader { id: montserratFont; source: "../../montserrat/Montserrat-Bold.ttf" }
    Text {
        font.family: montserratFont.name
        font.pointSize: 26
        text: qsTr("Do \"o\", \"O\", \"d\", \"D\" look OK?")
        anchors.centerIn: parent
    }

The glyphs of "o" and "d" are cut at the bottom side. See the screenshot

The issue occurs on Linux but cannot be observed on Windows, neither on Mac. It also occurs on QNX. Is it something related to FreeType?