You are absolutely right. In fact, I was the one who added and edited this release
This release is a good example. The audiobook is a "Autorisierte Lesefassung" which means "abridged version for readers". The name of this editor is not listed. Currently we have the original work "Little Brother" (writer "Cory Doctorow") and the German translation "Little Brother (Roman)" (writer "Cory Doctorow", translator "Uwe-Michael Gutzschhahn", translated version of "Little Brother").
We could add another work "Little Brother (German abridged version for readers)" (writer "Cory Doctorow", translator "Uwe-Michael Gutzschhahn", later version of "Little Brother (Roman)", additional writer "[unknown]"). Then the current webserver would show the relationship to the German translation, but not the relationship to the original "Little Brother".
We could also add "Little Brother (German abridged version for readers)" "is a translated version of" "Little Brother", so this original work is also shown on the webpage. That way we could represent "[unknown]" as additional editor, i.e. text editor.
Now these relationships contain redundant information:
a --abridged-version-of--> b --translated-version-of--> c
a --translated-version-of--> c
This is similar to our redundant relationships to the original author:
a --written-by--> x
b --written-by--> x
c --written-by--> x
Is this what we want? (I don't have an answer and hope to come to a consensus.)
I think this situation is similar to the arranger credits. There are arranger relationships for the recording and also for the work. The CSG explicitly does not want new works for every arrangement, only for those with multiple recordings.