I don't know, where, when and whom this happened , but there are two problems and a kind of workaround.
First add to your Container a new variable named "PAPERLESS_OCR_LANGUAGES" . You see the additinal 'S' at the end of the name.
Set both 'PAPERLESS_OCR_LANGUAGES' and 'PAPERLESS_OCR_LANGUAGE' to only one language. In your case that should be 'deu' without the quotes.
I hadn't enough time to test other combinations, but this worked for me.
I hope this will help you
Michael