Don't know German but this seems like a editing /typing error. They typed the almost same paragraph twice in the German version.

Yup, that's text that wasn't supposed to appear on the left page. I assume the translator moved it to the right page but then forgot to delete it from the left page.

But before filing yet another bug report for a language I don't even understand I'd like to be sure. :P

It's almost identical (pretty much same meaning phrased a tad differently), hence only one of those should be in there.

Assuming Avogadro6 is planning to report this to the dev, do you have an opinion on which version of that paragrpah is better German?

I'd go with the second one, and if the book's meant to be/look "identical" in either language, the layout seems to suggest that the first one was left in by accident.

Having said that, a native German speaker is better qualified to answer, if it's even till needed that is.

Thank you all.

As for which version is best, that should be up for the translator to decide. The devs don't speak German so they'll simply notify him as usual.

Just my opinion as a native speaker:
The left red box is a rough translation English -> German. Which means the English words were translated 1:1 to German, which results in an very 'jolty' sentence structure.
The right red box is formulated in a more elegant way.