Failing ES Promotion: apis Endpoint plugin test metadata api POST /api/endpoint/metadata when index is not empty

[mistic]

This failure is preventing the promotion of the current Elasticsearch nightly snapshot.

master/8.0: https://kibana-ci.elastic.co/job/elasticsearch+snapshots+verify/857/
7.x/7.9: https://kibana-ci.elastic.co/job/elasticsearch+snapshots+verify/856/
7.8/7.8.1: https://kibana-ci.elastic.co/job/elasticsearch+snapshots+verify/861/

For more information on the Elasticsearch snapshot promotion process: https://www.elastic.co/guide/en/kibana/master/development-es-snapshots.html

{ Error: [illegal_argument_exception] mapping fields [agent, endpoint, @timestamp, ecs, elastic, host, event] cannot be replaced during template composition
    at respond (/dev/shm/workspace/kibana/node_modules/elasticsearch/src/lib/transport.js:349:15)
    at checkRespForFailure (/dev/shm/workspace/kibana/node_modules/elasticsearch/src/lib/transport.js:306:7)
    at HttpConnector.<anonymous> (/dev/shm/workspace/kibana/node_modules/elasticsearch/src/lib/connectors/http.js:173:7)
    at IncomingMessage.wrapper (/dev/shm/workspace/kibana/node_modules/elasticsearch/node_modules/lodash/lodash.js:4929:19)
    at endReadableNT (_stream_readable.js:1145:12)
    at process._tickCallback (internal/process/next_tick.js:63:19)
  status: 400,
  displayName: 'BadRequest',
  message:
   '[illegal_argument_exception] mapping fields [agent, endpoint, @timestamp, ecs, elastic, host, event] cannot be replaced during template composition',
  path: '/metrics-endpoint.metadata-default-1',
  query: {},
  body:
   { error:
      { root_cause: [Array],
        type: 'illegal_argument_exception',
        reason:
         'mapping fields [agent, endpoint, @timestamp, ecs, elastic, host, event] cannot be replaced during template composition' },
     status: 400 },
  statusCode: 400,
  response:
   '{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"mapping fields [agent, endpoint, @timestamp, ecs, elastic, host, event] cannot be replaced during template composition"}],"type":"illegal_argument_exception","reason":"mapping fields [agent, endpoint, @timestamp, ecs, elastic, host, event] cannot be replaced during template composition"},"status":400}',
  toString: [Function],
  toJSON: [Function] }

[elasticmachine]

Pinging @elastic/endpoint-management (Team:Endpoint Management)

[jonathan-buttner]

@mistic I think we can close this issue. It should have been fixed in this PR: #68794