@suiteExperimenter I had the same issue the other day. you can see my thread in the suitescript group.
https://netsuiteprofessionals.slack.com/archives/C29HQS63G/p1610030180459700
you can see my record id in the "type" field below
var s = search.create({
type: "customrecord_vendor_invoice",
filters: ["custrecord_item_name", "is", mySublistItem],
columns: ["custrecord_item_name", "custrecord_shipped_quantity", "custrecord_unit_price", "custrecord_amount"]
})