Why are uploaded files lost after order guide are sent?

[Dat Phan]

I created the "Demo multi Row 001"multirow variable which has a field to reference the "sys_attachment".

When user upload file by the "Demo Attachment" attachment field. I cloned it. And I added it into "Demo Multi Row 001". But when the order guide is sumitted, the files in the something is deleted. What's the happend?

I used the on_change event for the "Demo Attachment" attachment field:

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
        return;
    }

    var attachmentAjax = new GlideAjax("DemoAttachmentUtil");
    attachmentAjax.addParam('sysparm_name', 'cloneAttachmentByAjax');

    attachmentAjax.addParam('sysparm_attachmentId', newValue);

    attachmentAjax.getXMLAnswer(function(response) {

        var newAttachmentId = "";
        if (response) {
            var resultData = JSON.parse(response);
            newAttachmentId = resultData.attachmentId;


            var jsonData = g_form.getValue('demo_multi_row_001');

            var lstFiles = [];
            if (jsonData) {

                lstFiles = JSON.parse(jsonData);
            }
            lstFiles.push({
                file_attachment: newAttachmentId
            });
            g_form.setValue('demo_multi_row_001', JSON.stringify(lstFiles));
        }
    });
}

, and script include "DemoAttachmentUtil":

var DemoAttachmentUtil = Class.create();
DemoAttachmentUtil.prototype = Object.extendsObject(AbstractAjaxProcessor, {
    cloneAttachmentByAjax: function() {
		var result = {
			status: 0,
			attachmentId: ''
		};
		try {
			var paramAttachmentId = this.getParameter('sysparm_attachmentId');
			result.attachmentId = this.copySingleAttachment(paramAttachmentId);
			result.status = 1;
		} catch(ex) {
			gs.info("TEST :" + ex);
			result.attachmentId = '';
		}
		return JSON.stringify(result);
	},
    copySingleAttachment: function(attachmentFileId) {
        var attRec;
        var orgAttachment = new GlideRecord('sys_attachment');
        orgAttachment.addQuery('sys_id', attachmentFileId);
        orgAttachment.query();
        if (orgAttachment.next()) {
            var cloneAttachment = new GlideRecord('sys_attachment');
            cloneAttachment.initialize();
            cloneAttachment.file_name = orgAttachment.file_name;
            cloneAttachment.content_type = orgAttachment.content_type;
            cloneAttachment.compressed = orgAttachment.compressed;
            cloneAttachment.table_name = orgAttachment.table_name;
            cloneAttachment.size_bytes = orgAttachment.size_bytes;
            cloneAttachment.size_compressed = orgAttachment.size_compressed;
            cloneAttachment.table_sys_id = orgAttachment.table_sys_id;
            attRec = cloneAttachment.insert();
        }

        var attDoc = new GlideRecord('sys_attachment_doc');
        attDoc.addQuery('sys_attachment', orgAttachment.sys_id);
        attDoc.query();
        while (attDoc.next()) {
            var attDocCopy = new GlideRecord('sys_attachment_doc');
            attDocCopy.initialize();
            attDocCopy.sys_attachment = attRec;
            attDocCopy.position = attDoc.position;
            attDocCopy.length = attDoc.length;
            attDocCopy.data = attDoc.data;
            attDocCopy.insert();
        }
        return attRec;
    },
    isPublish: function() {
        return true;
    },
    type: 'DemoAttachmentUtil'
});