Auto-resize doesn't make use of the whole screen, a bit on the bottom and right side appears to be ignored. Furthermore, it isn't always stable, sometimes the window will keep moving to the left when repeatable doing the auto-resize.
I suspect Cinnamon is sending incorrect window-placement and/or size to Qt. It might be that it includes the box-shadow in size and position, but not in window placement.
Auto-resize doesn't make use of the whole screen, a bit on the bottom and right side appears to be ignored. Furthermore, it isn't always stable, sometimes the window will keep moving to the left when repeatable doing the auto-resize.
I suspect Cinnamon is sending incorrect window-placement and/or size to Qt. It might be that it includes the box-shadow in size and position, but not in window placement.