Setting background color to Tab reverts the Triangular shape back to Rounded

I am using a QTabWidget with a triangular tab shape. However, I want to change the background color of the selected tab to something else than the default, but I cannot because setting the background color for the selected tab reverts the triangular shape back to default rounded shape.

I am using this style sheet

QTabWidget {
    background-color: rgb(0, 0, 0);
    qproperty-tabShape: Triangular;
}

QTabBar::tab:selected {
    color: green;
    background-color: pink;
}

QTabBar::tab:!selected {
    color: red;
}

Please find the attached example project which demonstrates this effect. Also attached a screenshot of the end result