Qt5.8/Mac : unreadable text of selected QTabWidget item because rendered in white (Fusion style)

Qt 5.8.0 introduced an unhappy change: when using the Fusion application style on Mac (or any other style that's not the native style), the text of the selected tab in a QTabWidget is rendered in white or a very close colour. With the default background this makes the text nearly impossible to read.

The Fusion style is a very convenient and nicely fitting-in style to make the QTabWidget appropriate for use in tabbed editors, much more so than the document mode of the same widget in the Macintosh style.

This behaviour doesn't occur when the widget is in "document" mode. I do not observe this on Linux but I DO observe it on Mac using the XCB QPA plugin. Which suggests that the underlying change is in a platform-specific section that is not part of the QPA plugin. Where should I start searching?

Simple demonstrator: https://github.com/RJVB/QtTabDialogTest

Run with `-style fusion` or `-style windows`.