Inconsistent sort order on identical queries

Hi Folks,

I have a two node cluster with replication (ES 1.7). Querying either one of the nodes directly with the same exact query, consecutively, produces different sorts of results. While the weighted fields produce correctly generated scores for the documents at the top of the sort, the remaining documents all have the same score of 1.0. I understand that those documents' ordering may be arbitrary, but I would expect the same arbitrary order to come back each time for the same query. Any ideas as to why that would not be the case? Here is the query body:

{
  "filter": {
    "terms": {
      "postal_code": [
        "63348",
        "63366",
        "63367",
        "63368",
        "63385"
      ]
    }
  },
  "query": {
    "function_score": {
      "query": {
        "match_all": {
          
        }
      },
      "functions": [
        {
          "filter": {
            "term": {
              "is_verified": true
            }
          },
          "weight": 1.5
        },
        {
          "filter": {
            "term": {
              "is_paid": true
            }
          },
          "weight": 3
        }
      ],
      "score_mode": "multiply"
    }
  },
  "from": 0,
  "aggs": {
    "postal_code_facet": {
      "filter": {
        "terms": {
          "postal_code": [
            "63348",
            "63366",
            "63367",
            "63368",
            "63385"
          ]
        }
      },
      "aggs": {
        "inner_postal_code_facet": {
          "terms": {
            "field": "postal_code_facet",
            "size": 100
          }
        }
      }
    },
    "categories_facet": {
      "filter": {
        "terms": {
          "postal_code": [
            "63348",
            "63366",
            "63367",
            "63368",
            "63385"
          ]
        }
      },
      "aggs": {
        "inner_categories_facet": {
          "terms": {
            "field": "categories_facet",
            "size": 100
          }
        }
      }
    },
    "locality_region_facet": {
      "filter": {
        "terms": {
          "postal_code": [
            "63348",
            "63366",
            "63367",
            "63368",
            "63385"
          ]
        }
      },
      "aggs": {
        "inner_locality_region_facet": {
          "terms": {
            "field": "locality_region_facet",
            "size": 100
          }
        }
      }
    }
  },
  "size": 12
}