Since migrating to ES5 the multi_match query matches documents with score 0

[reza.ro]

Since the update the fuzzy query matches documents and inner explain shows a ConstantScore with boost 0.

GET test_automation24_shop_2_article/_search
{
  "size": 100,
  "_source": "children.title_en",
  "query": {
"nested": {
  "query": {
    "multi_match": {
      "type": "most_fields",
      "query": "200/125 xg",
      "fuzziness": 1,
      "prefix_length": 1,
      "minimum_should_match": "99%",
      "fields": [
        "children.title_en.4s_whitespaceAnalyzer"
      ]
    }
  },
  "path": "children",
  "inner_hits": {
    "explain": true
  }
}
  }
}

and the result of explain for inner hit shows this:

 "_explanation": {
	"value": 0,
	"description": "sum of:",
	"details": [
	  {
		"value": 0,
		"description": "sum of:",
		"details": [
		  {
			"value": 0,
			"description": "ConstantScore(children.title_en.4s_whitespaceAnalyzer:x), product of:",
			"details": [
			  {
				"value": 0,
				"description": "boost",
				"details": []
			  },
			  {
				"value": 1,
				"description": "queryNorm",
				"details": []
			  }
			]
		  }
		]
	  }
	]
}