Inconsistent counts for searchapi2's search_objects with and without sort applied

[jayrbolton]

Reported by Erik on Jira: https://kbase-jira.atlassian.net/browse/PTV-1583

Queries I can look at in CI

{
	"jsonrpc": "2.0",
	"id": "afdd6432-d66f-44a3-a491-e713f3a67835",
	"method": "search_objects",
	"params": {
		"query": {
			"bool": {
				"must": [{
					"term": {
						"tags": "refdata"
					}
				}, {
					"term": {
						"source": "RefSeq"
					}
				}]
			}
		},
		"only_public": true,
		"indexes": ["genome"],
		"size": 0,
		"from": 0,
		"track_total_hits": true
	}
}

And with the sort but no search term:

{
	"jsonrpc": "2.0",
	"id": "197034cd-cee7-48ea-a6fe-3994dcf20443",
	"method": "search_objects",
	"params": {
		"query": {
			"bool": {
				"must": [{
					"term": {
						"tags": "refdata"
					}
				}, {
					"term": {
						"source": "RefSeq"
					}
				}]
			}
		},
		"sort": [{
			"scientific_name.raw": {
				"order": "asc"
			}
		}, "_score"],
		"only_public": true,
		"indexes": ["genome"],
		"size": 20,
		"from": 0,
		"track_total_hits": true
	}
}

with sort and user search for “prochlorococcus”:

{
	"jsonrpc": "2.0",
	"id": "fd697975-bbd5-473b-b24b-da3bf43169d9",
	"method": "search_objects",
	"params": {
		"query": {
			"bool": {
				"must": [{
					"term": {
						"tags": "refdata"
					}
				}, {
					"term": {
						"source": "RefSeq"
					}
				}, {
					"match": {
						"scientific_name": {
							"query": "prochlorococcus"
						}
					}
				}]
			}
		},
		"sort": [{
			"scientific_name.raw": {
				"order": "asc"
			}
		}, "_score"],
		"only_public": true,
		"indexes": ["genome"],
		"size": 20,
		"from": 0,
		"track_total_hits": true
	}
}