Missing 'mouseMoveEvent' with native widgets on Wayland

When using native widgets on Wayland, 'mouseMoveEvents' are not triggered when moving the mouse over a widget that is set as the central widget of a QMainWindow unless a mouse button is pressed.

To reproduce:

1) compile attached sample program "main.cpp"
2) run the program under Wayland
3) move the mouse over the widget without pressing any button
4) observe the qDebug output

Result: No output is generated. The "mouseMoveEvent" is not triggered while moving the mouse cursor.

Expected result: The position of the mouse should be printed while moving the mouse cursor.

Notes:

• The "mouseMoveEvent" is triggered as expected when pressing a mouse button while moving the mouse cursor.
• It works as expected when using "alien widgets" instead of "native widgets" (s. [1]), i.e. removing the call to 'setAttribute(Qt::WA_NativeWindow);' in line 18 of the sample program.
• This works as expected on X11, also with native widgets" in use.
• This was originally reported against LibreOffice, where this is an issue when the new Qt 5 integration is used on Wayland, s. [2].

[1] https://doc.qt.io/qt-5/qwidget.html#native-widgets-vs-alien-widgets
[2] https://bugs.documentfoundation.org/show_bug.cgi?id=122293