Hi smolo,
did you check under Subscribers > Profile Page > General > Profile Page if the tag {profile_form} appear twice?
Check even if this happens in the "Text" view (not just the Visual one).
If the profile_form code is okay then check List building > Subscription form fields, buttons... > Main profile fields if every field appear only once (in case you added custom form fields).
Hi, probably is a problem with the German translation. Check the profile configuration panel as suggested, I'll try to get in touch with the German community.