ElasticSearch returns fragments significantly over fragment size

I have the following to set my marker in elasticsearch

{ 
  pre_tags: ["<b>"], 
  post_tags: ["</b>"], 
  fields: { 
    title: { number_of_fragments: 0 },                                           
    body:  { number_of_fragments: 1, fragment_size: 200, type: "plain" }
  }
}

      

        
        
        
      

    

however, sometimes I get a body selection over 300 characters and I'm not sure why this is rare, but from time to time the search result will go through with a very long search chunk.

My workaround is that I am trimming the result manually, but I would rather not.