Wayland: cannot resize a window to its minimum height

I cannot resize a window to its reported minimum height on Wayland, but I can do that on X11 (using the xcb plugin). I observe this bug with QMainWindow with a single QLabel or QPushButton set as its central widget (see the attachment).

Expected: When I drag the mouse to reduce the window size, the window allows me to do that until its minimum size (height) is reached.

Observed: When I drag the mouse to reduce the window size, the actual minimum size that I can resize to is greater that its reported minimum size (value of property minimumSize).

Steps to reproduce:

1. Compile attached main.cc (using CMakeLists.txt).
2. If you run with QT_QPA_PLATFORM=xcb, you can resize the window to its reported minimum height.
3. if you run with QT_QPA_PLATFORM=wayland, you cannot resize it to the reported minimum height.