NPE in GoupingNode

I get an NPE within Teiid's GroupingNode.initialize when executing the following SQL
SELECT XMLELEMENT(NAME metadata,
XMLFOREST(objectName as objectName),
(SELECT XMLAGG(XMLELEMENT(name subTypes,
XMLFOREST(subType)))
FROM chorus_metadata.property_filtered b
WHERE a.objectName=b.objectName
GROUP BY subType)
)
FROM chorus_metadata.property_filtered a
GROUP BY objectName
LIMIT 1

chorus_metadata.property_filtered is an internal materialized view.