Processor QueryCassandra crashes if CQL query "SELECT" has only 1 returned field (ArrayIndexOutOfBoundsException)

STEP to reproduce :
Use QueryCassandra processor
CQL select query : SELECT txt_content as tcontent from url_content where url_id=${dd.id}
Output Format : Avro

==> ArrayIndexOutOfBoundsException

If I change CQL query to SELECT url_id, txt_content as tcontent from url_content where url_id=${dd.id}

==> Ok