Here are some example images of what I'm seeing on MacOS.

This is without the Fusion style applied.
1DB4176E-C198-43FD-8E95-C3F3F882168C.png

This is with the Fusion style applied. Everything else is the same.
A3AAEB8C-4697-40D4-9DEF-7C3600FD8B68.png

On Windows the spinboxes completely disappear (I think they're hidden below the lower edge of each cell).