Create a menu entry in kmenueditor that calls a command line application (say, "top"), with "Run in Terminal" (on the "Advanced" tab) enabled.
Try to start it from the application menu.
konsole starts successfully on Wayland now too, with or without an icon set.
Still works on X11/xcb as well.
Additional debug output confirms that konsole is called with "-qwindowicon someicon" now, but only if there actually is an icon set in the .desktop file.