ElasticSearch parent child mapping & ttl on parent

gistfile1.txt

curl -XPUT http://localhost:9200/test/parent/_mapping -d '{"parent" : {"_ttl": {"enabled": true}}}'

curl -XPUT http://localhost:9200/test/child/_mapping -d '{"child": {"_parent": {"type": "parent"}}   }'

curl -XPUT http://localhost:9200/test/parent/parent1?ttl=60000 -d '{"name" : "parent1"}'

curl -XPUT http://localhost:9200/test/child/child1?parent=parent1 -d '{"name" : "child1"}'

curl -XPUT http://localhost:9200/test/child/child2?parent=parent1 -d '{"name" : "child2"}'

After a few minutes parent1 is deleted but children are not.
Also:

curl -XGET http://localhost:9200/test/child/child1?fields=_parent
{"_index":"test","_type":"child","_id":"child1","_version":1,"exists":true,"fields":{"_parent":"parent1"}}