Hello @dh54220 ,
For me, granite/ui/components/coral/foundation/form/multifield is perfectly working. Maybe you missed any of the structures.
For reference, I added a sample code. Can you try this?
<?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="Component"
sling:resourceType="cq/gui/components/authoring/dialog">
<content
jcr:primaryType="nt:unstructured"
sling:resourceType="granite/ui/components/coral/foundation/fixedcolumns">
<items jcr:primaryType="nt:unstructured">
<column
jcr:primaryType="nt:unstructured"
sling:resourceType="granite/ui/components/coral/foundation/container">
<items jcr:primaryType="nt:unstructured">
<rows
jcr:primaryType="nt:unstructured"
sling:resourceType="granite/ui/components/coral/foundation/form/multifield"
composite="{Boolean}true"
fieldDescription="Click 'Add' to add rows"
fieldLabel="Rows">
<field
jcr:primaryType="nt:unstructured"
sling:resourceType="granite/ui/components/coral/foundation/container"
name="./rows">
<items jcr:primaryType="nt:unstructured">
<!-- Multifield Items -->
</items>
</field>
</rows>
</items>
</column>
</items>
</content>
</jcr:root>