Can you replace

data.sc_catalog = $sp.getParameter('catalog_sys_id');

with

var cat = new GlideRecord('sc_category');

cat.addQuery('sys_id', data.category_id);

cat.query();

if (cat.next()) {

        data.sc_catalog = cat.sc_catalog;

}

if(categryID == '' || categryID == null )

        data.sc_catalog = $sp.getParameter("catalog_sys_id");

and see if it works.