Create HR case using Request catalog item topic block

[poornimanar]

Hello,

I am facing issue with the OOB Request Catalog item (LLM) Topic Block,  I have a requirement where I need to create a case from VA with one particular record producer.

In order to achieve this , I have created a custom topic and included a OOB topic block "Request Catalog Item(LLM) but with this topic block, when I click on the submit for the first time, it fails to create a case and again it gives the options to submit, add attachments, Make changes when I again click on Submit it successfully creates the case.

This is the script in oob topic block for creating the HR case,

(function execute() {

    var itemJson = JSON.parse(vaVars.itemJSON);

    var variablesObj = {};

    var attachmentIds = [];

    for (i = 0; i < itemJson.variables.length; i++) {

        variablesObj[itemJson.variables[i].name] = itemJson.variables[i].value;

        if (itemJson.variables[i].type === 33)

            attachmentIds.push(itemJson.variables[i].value);

    }

    vaVars.variables = JSON.stringify(variablesObj);

    var reqObject = {

        "sysparm_id": itemJson.sys_id,

        "sysparm_action": 'execute_producer',

        "variables": variablesObj,

        "engagement_channel": 'va',

        "contact_type": 'virtual_agent'

    }

    vaVars.status = "error";

    var response = new sn_sc.CatItem(itemJson.sys_id).submitProducer(reqObject);

    if (response) {

        vaVars.status = "success";

        vaVars.record_id = response.sys_id;

        vaVars.record_table = response.table;

        // add attachment to record

        var mediaLinksFormAttachment = vaVars.media_links_form_attachment.split(',');

        for (var i in mediaLinksFormAttachment)

            vaSystem.attachToRecord(mediaLinksFormAttachment[i], response.table, response.sys_id);

        // move attachment variable to record

        // ONLY try to move attachments if we have valid files to move

        if (attachmentIds && attachmentIds.length > 0) {

        var gr = new GlideRecord('sys_attachment');

        gr.addQuery('sys_id', 'IN', attachmentIds);

        gr.query();

        while (gr.next()) {

            gr.setValue('table_name', 'ZZ_YY' + response.table);

            gr.setValue('table_sys_id', response.sys_id);

            gr.update();

        }

     }

    }

})()

Can someone please check and help me on this? 
There is also one more issue, with "contact_type": 'virtual_agent' , after creating the case the source field still updates with self service , how to update it with virtual agent.