Phrase Highlighting Works Incorrectly on ES 2.1.1 and 2.2.0

Elastic Stack Elasticsearch
1

This is an issue with Elastic Search 2.1.1 and same on 2.2.0.

I have this record indexed in elastic :

{
	"WordB" : "Cat",
	"WordC" : "Dog",
	"WordA" : "Black",
	"message" : "Black Dog",
}

When I run the following query :

{
	"query" : {
		"bool" : {
			"must" : {
				"bool" : {
					"should" : [{
							"multi_match" : {
								"query" : "Black Dog",
								"fields" : [
									"WordA",
									"WordB",
									"WordC",
									"message"
								],
								"type" : "phrase",
								"analyzer" : "default_search"
							}
						}
					]
				}
			}
		}
	},
	"highlight" : {
		"pre_tags" : [
			"<b>"
		],
		"post_tags" : [
			"</b>"
		],
		"fragment_size" : 0,
		"number_of_fragments" : 0,
		"require_field_match" : false,
		"fields" : {
			"WordA" : {},
			"WordB" : {},
			"WordC" : {},
			"message" : {}
		}
	}
}

I get the following result :

{
	"took" : 11,
	"timed_out" : false,
	"_shards" : {
		"total" : 190,
		"successful" : 190,
		"failed" : 0
	},
	"hits" : {
		"total" : 1,
		"max_score" : 1.9719523,
		"hits" : [{
				"_index" : "fts-english",
				"_type" : "Document",
				"_id" : "AVJk37BCIfOJ7fqrcZCp",
				"_score" : 1.9719523,
				"_source" : {
					"WordB" : "Cat",
					"WordC" : "Dog",
					"WordA" : "Black",
					"message" : "Black Dog"
				},
				"highlight" : {
					"WordC" : [
						"<b>Dog</b>"
					],
					"WordA" : [
						"<b>Black</b>"
					],
					"message" : [
						"<b>Black</b> <b>Dog</b>"
					]
				}
			}
		]
	}

}

But I searched for a phrase, so why do I get highlighting of individual words in fields that don 't contain the full phrase? I expect to get in this case only the "message" field highlighted but not the other two fields.

I should also mention that:

  1. Other records containing just the word "Black" are not returned by the query, which indicates that the phrase query itself runs correctly, and the issue is only in the highlighting.
  2. The same worked correctly on Elastic Search version 1.6.0, and I am seeing this issue only with version 2.1.1 and 2.2.0.
2

I am having the same issue with ES version 2.3.0 - while the phrase highlighting worked fine on version 1.7.2 it is now highlighting the individual terms as well as the phrases. Does anyone have any ideas on how to fix this?