When coping a reference from left column and paste it into the translation column "Vorlage:Sfn" in red. the clipboad contains:"Template:Sfn" The shortened footnote template does not exist in German. I have no idea, how to create this template.
Topic on Talk:Content translation
Thanks for the feedback, @Hans Haase,
References use templates to structure their content. Unfortunately, templates are created independently on each wiki, so the Content translation tool needs to find the corresponding templates and parameters in each wiki to copy the information over. In some cases, those templates may not exist on a given wiki.