If you create a category with a double quoted word, for example: This is "crazy". It ends up in the database with quotes and is displayed with quotes when rendered in html as simple text. However, when it is used as the value for an edit control, e.g. in Edit Category (action=editcat) the quoted part does not appear.
in /admin/categories.php find:
show_input_row($lang['field_category_name'], "cat_name", $result['cat_name'], $textinput_size);
and replace it with:
show_input_row($lang['field_category_name'], "cat_name", str_replace("\"", """, $result['cat_name']), $textinput_size);