Qt5 no longer shows window list in macOS dock

A Qt4 application showed the list of windows it had in the macOS dock, a Qt5 application does not, unlike native macOS applications. I've tested this with a variety of Qt5-based applications on macOS and all exhibit the same bug.

To begin with, here is how it properly looked like in Qt4: https://i.stack.imgur.com/l7jCp.png. The application has two windows and both are listed in the dock along with a little icon signifying that it's a window. Here is how it looks like in Qt5: https://i.stack.imgur.com/EI0RV.png the application window list is missing.

I have tested several open-source, Qt5 applications for this behaviour and as far as I can see all of them are affected by this bug.

Tiled on macOS, no window list: https://i.imgur.com/JHzRpmK.png
Tiled on Ubuntu, window list present: https://i.imgur.com/6OMg4f3.png

PacketSenter on macOS, no window list: https://i.imgur.com/cPATKIR.png
PacketSender on Ubuntu, window list present: https://i.imgur.com/Aw636gJ.png

git-cola also exhibits this behaviour.

Unless proven otherwise, I believe all Qt5 applications on macOS have this bug.