Using must finds document, using should doesn't - why?

Elastic Stack Elasticsearch
2

i tested the same querys with my local data and it works (with default analyzer) you had the json query that you send to Elasticsearch? try to get your json and test in Elasticsearch with marvel sense, or the plugin head! it can be a problem with double slash, corrupted array...
my test query :

{
  "query": {
    "bool": {
      "should": [
        {
          "match_phrase": {
            "os_version": "firefox 6"
          }
        },
        {
          "match_phrase": {
            "os_version": "firefox 06"
          }
        }
      ],
      "minimum_number_should_match": 1
    }
  }
}