Fusion's problem with multi-screen on Wayland

If the second screen is scaled under Wayland, the icons of sub-menus might have a wrong size on the first screen with Fusion. The same thing happens with first and second reversed. Apparently, the Wayland compositor isn't relevant (tested on kwin_wayland, labwc and niri) Please see the attached screenshot.

This does not happen with the Kvantum and Breeze widget styles.

Sorry, there are too many factors that I can't logically rule out — especially, the icon engine — but the fact that it happens only on sub-menus, only with multi-screen scaling on Wayland, and only with Qt's default style may be indicative of a deeper problem. Hence reporting it here.