const afterSubmit = (scriptContext) => {
            // grab the file from the file cabinet.
            const folderSearchObj = search.create({
                type: "folder",
                filters:
                [
                   ["name","contains","Attachments"],
                   "AND",
                   ["parent","anyof","[SOME_INTERNAL_ID]"]
                ],
                columns:
                [
                   search.createColumn({name: "internalid", join: "file", label: "Internal ID"})
                ]
             });
             const resultSet = folderSearchObj.run().getRange({
                start: 0,
                end: 1
             });
             const fileId = resultSet[0].getValue({
                name: "internalid",
                join: "file"
             });
            log.debug('fileId:', fileId);
            const newRecordId = scriptContext.newRecord.id;
            log.debug('new Record ID: ', newRecordId);
            record.attach({
                record: {
                    type: 'file',
                    id: fileId
                },
                to: {
                    type: record.Type.JOURNAL_ENTRY,
                    id: newRecordId
                }
            });
        }
The resultSet is jank but it's for testing right now.
This is what I get when it runs:
{
   type: "error.SuiteScriptError",
   name: "RCRD_DSNT_EXIST",
   message: "That record does not exist. id2: 7344035",
   cause: {
      type: "internal error",
      code: "RCRD_DSNT_EXIST",
      details: "That record does not exist. id2: 7344035",
      ],
      notifyOff: false
   },
   notifyOff: false,
   userFacing: true
}
Maybe I need to clear the cache because I was testing in the console with the variable called "id2"?