Beforehand: this is a low prio bug - and I must say that I really really like the new-to-9.5 factbook facets in the library. I wondered why factbook would get an entry for every book - but now I know: to filter the library. What commentaries do I have on Habakuk? Are there books on Islam? Those are very valid user questions that now can be answered without the user tagging their books and beyond the often unreliable subject fields - thank you for this new functionality.
Now to the bug: in the German UI the factbook facet groups (or whatever those second level filter facets may be called) in the Store view are not showing their names, as they do in the Yours view:

Note: this works as it should in the English UI