We do have a section in our form with several Admin-only fields. The internal section is led by a section break. The section break itself and all fields inside the internal section are admin-only. We do have about 10 dropdown fields in the internal section.
Unfortunately the caption of the section break is posted in the {all_fields} tag inside the user notification email. We even tried {all_fields:noadmin} with no success. It seems, that there could be a problem with Admin-only section breaks?