Nope. No configuration at all, it’s just that Netlify specifically has a pending bug where if more than one `Accept-Language`s are sent, then the language redirects don’t work.
You can see the related issue here: https://community.netlify.com/t/language-based-redirect-only-works-when-1-browser-language-set/4252/6
To see that it’s indeed a bug, try issuing a request with a single language like so:
curl -H 'Accept-Language: de' -L -v -s https://YOUR_SITE.netlify.com 1> /dev/null
Let me know if the issue is unrelated to the bug