Suggestion Size

hello, I have some Issue with the number of suggestions to return field (size)

the first query is size equal to 1

    POST ja-search-data-prod/_search
    {
      "suggest": {
        "promotion-suggest": {
          "text": "1.8",
          "completion": {
            "field": "promoSuggest",
            "size": 1
          }
        }
      }
    }

the result is right only 1

Capture1

the same query with different size, but big size like 100
return right only 3 suggestions

Capture2

now the issue with executing the same query with size = 3
need to return all 3 as size equals to 100, between them need to be no difference

that the result for size = 3

Capture3

exactly is return only 2, it is bug or I do something wrong?

some help please?