Elasticsearch NPE during highlighting

gistfile1.txt

#!/bin/sh
#
#  Start 2 ES nodes with default settings before running this script
#
curl -XDELETE http://localhost:9200/testidx
curl -XPUT http://localhost:9200/testidx -d '{
    "settings" : {
        "index" : {
            "number_of_shards" : 1,
            "number_of_replicas" : 0
        }
    },
    "mappings" : {
        "rec" : {
            "_source" : { "enabled" : false },
            "properties" : {
	        "from" : { "type": "string", "store": "yes" }
            }
        }
    }
}'
curl -XPUT http://localhost:9200/testidx/rec/1 -d '{
    "from" : ["user3@test.com","user2@test.com","user5@test.com"]
}'
echo
curl -XPOST http://localhost:9200/testidx/_refresh
echo
curl localhost:9200/testidx/_search -d '{
    "highlight": {
         "fields":{"from":{"number_of_fragments":0}}
    },
    "fields":["*"],
    "size":10,
    "sort":["_score"],
    "query":{
        "query_string":{
            "default_field":"from",
            "query":"*:*"
         }
    }
}' && echo
curl localhost:9201/testidx/_search -d '{
    "highlight": {
         "fields":{"from":{"number_of_fragments":0}}
    },
    "fields":["*"],
    "size":10,
    "sort":["_score"],
    "query":{
        "query_string":{
            "default_field":"from",
            "query":"*:*"
         }
    }
}' && echo