plasmate.desktop has the Icon= set to plasmagik which only exist in oxygen icons.
I can confirm this. Just checked it on Arch Linux with Plasma 5.9.3.
can you post a screenshot of the app. thanks
Here is the screenshot of the menu entry: http://i.imgur.com/GJkCIrs.png And here of the app icon in the title bar: http://i.imgur.com/Gn7bYSN.png
Git commit 06c942e4026b31f2cfeeaa68af9376c8ecd33fb8 by andreas kainz. Committed on 27/04/2017 at 20:46. Pushed by andreask into branch 'master'. BUG 376780 add plasmate icon A +1 -0 icons-dark/preferences/32/plasmagik.svg A +1 -0 icons/preferences/32/plasmagik.svg https://commits.kde.org/breeze-icons/06c942e4026b31f2cfeeaa68af9376c8ecd33fb8