Hi there,
I noticed in my latest Excel version (Beta Channel), that when I insert a stock icon, the context menu and the task pane are showing an unwell translated text. I would suggest to use Grafik formatieren instead of Formatgrafik. In English, we have Format Graphic for stock icons too.
For reproducing, please select Insert » Pictures » Stock Images » Icons » Anyone of those, in German Einfügen » Bilder » Archivbilder » Piktogramme » Anyone of those.
Additional note: the problem is also present in Word and PowerPoint too.
Best,
Mourad