systemmontor is showing a generic Wayland icon. It's resourceName is systemmonitor but there is no corresponding desktop file, so no Icon is shown. Under X11 it shows the same icon as ksysguard.
Then create a new .desktop file and set NoDisplay=true so it doesn't appear in menus. Can you take care of that?
Yeah, no problem. I'll do it.
Git commit 97a88917a546c426be73e6bff0b248135aca7033 by Andrius Štikonas. Committed on 14/10/2017 at 02:13. Pushed by stikonas into branch 'master'. systemmonitor: Add a desktop file. M +1 -0 systemmonitor/CMakeLists.txt M +3 -0 systemmonitor/main.cpp A +6 -0 systemmonitor/org.kde.systemmonitor.desktop https://commits.kde.org/plasma-workspace/97a88917a546c426be73e6bff0b248135aca7033