ES 7.12 - Java rest high level - multi_terms aggregation - response error

Hi there,
I've a request using SearchTemplateRequest
the request script uses "multi_terms" aggregation

I can see in the logs that the response comes as expected but the java rest high level throws an exception saying

org.elasticsearch.common.xcontent.NamedObjectNotFoundException:  unknown field [multi_terms]

looks like it is unsupported by the java client

Thanks for any help

Request script ref:

{
  "size": 0, 
  "query": {
    "bool": {
      "filter": [
        { "term": {
          "process.tag.telemetry@sdk@name" : "opentelemetry"
        }},
        { "exists": {
          "field": "process.tag.telemetry@sdk@name"
        }},
        { "term": {
          "tag.span@kind" : "server"
        }},
        { "term": {
          "process.serviceName" : "ServiceName"
        }},
        { "term": {
          "process.tag.hostname" : "HostName"
        }}
      ]
    }
  },
    "aggs": {
    "spans": {
      "multi_terms": {
        "terms": [
          {"field": "operationName","missing": ""},
          {"field": "tag.http@url","missing": ""}
          ],
          "size": 100
      },
      "aggs": {
        "ids": {
          "terms": {
            "field": "spanID","size": 100
          }
        }
      }
    }
  },
  "fields": [
    "operationName"
  ]
  ,
  "_source": false
}