[Reg 5.5 -> 5.6] TableView with non-integral header's height loops endlessly

Reproduction:
Run "TableView Example" with custom headerDelegate in TableViewStyle (notice height: 20.6):

TableView {
    (...)
    style: TableViewStyle {
        headerDelegate: Rectangle {
            height: 20.6
            Text {
                anchors.fill: parent
                text: styleData.value
            }
        }
    }
}

Program loops endlessly immediately after starting, gui is unresponsive.

With additional debug code:

TableView {
    (...)
    Component.onCompleted: {
        flickableItem.contentYChanged.connect(function () {
                console.debug("contentY", flickableItem.contentY);
        });
    }
}

we can see that flickableItem.contentY oscillates between negative header's height and its rounded value, so in this case between -20.6 and and -21.

Any fraction between 0.5 and 1 causes infinite loop immediately after table creation. Fractions between 0 and 0.5 sometimes cause loop after scrolling/filtering.

Full modified example main.qml attached.