AEM 6.3 coral ui 3 Touch UI - Entered Content Disappearing on multifield, After Validation Error of text field

1. Remove the text in the Section Header field.
2. Submit. You will see now that the fields under the multifield vanished and bad UI .
3. Enter the Section Header text.
4. Submit. And edit the cmp you see all fields normal.

On edit of cmp:

On submit by removing the text-field value:

Here is the code for cmp:

<?xml version="1.0" encoding="UTF-8"?>
<jcr:root xmlns:sling="http://sling.apache.org/jcr/sling/1.0" xmlns:cq="http://www.day.com/jcr/cq/1.0" xmlns:jcr="http://www.jcp.org/jcr/1.0" xmlns:nt="http://www.jcp.org/jcr/nt/1.0"
    jcr:primaryType="nt:unstructured"
    jcr:title="Related Articles"
    sling:resourceType="cq/gui/components/authoring/dialog"
    extraClientlibs="cq.relatedarticles.dialog">
    <content
        jcr:primaryType="nt:unstructured"
        sling:resourceType="granite/ui/components/coral/foundation/tabs">
        <items jcr:primaryType="nt:unstructured">
            <basic
                jcr:primaryType="nt:unstructured"
                jcr:title="Configuration"
                sling:resourceType="granite/ui/components/coral/foundation/fixedcolumns">
                <items jcr:primaryType="nt:unstructured">
                    <columns
                        jcr:primaryType="nt:unstructured"
                        sling:resourceType="granite/ui/components/coral/foundation/container">
                        <items jcr:primaryType="nt:unstructured">
                            <sectionHeader
                                jcr:primaryType="nt:unstructured"
                                sling:resourceType="granite/ui/components/coral/foundation/form/textfield"
                                fieldDescription="Suggested limit of 40 characters"
                                fieldLabel="Section Header"
                                name="./sectionHeader"
                                required="{Boolean}true"/>
                            <article
                                jcr:primaryType="nt:unstructured"
                                sling:resourceType="aarp/components/modular/granite/fixedlistmultifield/relatedarticle"
                                fieldDescription="Click the '+' to add a new article."
                                fieldLabel="Article"/>
                        </items>
                    </columns>
                </items>
            </basic>
        </items>
    </content>
</jcr:root>

Multifield code:

<?xml version="1.0" encoding="UTF-8"?>
<jcr:root xmlns:sling="http://sling.apache.org/jcr/sling/1.0" xmlns:jcr="http://www.jcp.org/jcr/1.0" xmlns:nt="http://www.jcp.org/jcr/nt/1.0"
    jcr:primaryType="nt:unstructured"
    sling:resourceType="granite/ui/components/foundation/form/fieldset"
    aarp-commons-nested="JSON_STORE"
    name="./article">
    <layout
        jcr:primaryType="nt:unstructured"
        sling:resourceType="granite/ui/components/coral/foundation/fixedcolumns"
        method="absolute"/>
    <items jcr:primaryType="nt:unstructured">
        <column
            jcr:primaryType="nt:unstructured"
            sling:resourceType="granite/ui/components/coral/foundation/container">
            <items jcr:primaryType="nt:unstructured">
                <articleUrl
                    jcr:primaryType="nt:unstructured"
                    sling:resourceType="granite/ui/components/coral/foundation/form/pathbrowser"
                    fieldLabel="Article Url"
                    name="./articleUrl"
                    required="{Boolean}true"
                    rootPath="/content"/>
                <articleHeading
                    jcr:primaryType="nt:unstructured"
                    sling:resourceType="granite/ui/components/coral/foundation/form/textfield"
                    fieldLabel="Article Heading"
                    name="./articleHeading"
                    required="{Boolean}true"/>
                <articleSource
                    jcr:primaryType="nt:unstructured"
                    sling:resourceType="granite/ui/components/coral/foundation/form/textfield"
                    fieldLabel="Article Source"
                    name="./articleSource"
                    required="{Boolean}true"/>
            </items>
        </column>
    </items>
</jcr:root>