word_separation empty in some cases when Duden has information

[tbm]

You're only looking for Worttrennung but in some cases Duden says:

• Von Duden empfohlene Trennung
• Alle Trennmöglichkeiten

Since you're returning a list of word parts already, I don't think you can return multiple results, so maybe just use the first one (Von Duden empfohlene Trennung)?

Here's one example:
https://www.duden.de/rechtschreibung/manoevrierfaehig