I found out, that it's not the URLs on this page, but the very same URLs that
get redirected by Status Code 302.
In the navigation there is a URL /de/fokus-events/2.-weltkrieg/index.html
which get's redirected to /de/fokus-events/specials/index.html?SID=66#Main66.
This produces the error Bad Request (400).
If I remove the #Main66 part in the CMS, all get's downloaded perfectly.