Wrong date format pattern for origination date in doc?

[YuWatanabe]

Hello .

I would like to confirm the pattern used to parse origination date from index name.
I am using elasticsearch 7.17.4 .

Index lifecycle management settings in Elasticsearch | Elasticsearch Guide...

It says,

The index name must match the pattern ^.*-{date_format}-\\d+ , where the date_format is yyyy.MM.dd

But origination_date was parsed from index name zoom-meetings-2022.07.06 .

GET zoom-meetings-2022.07.06/_settings
{
  "zoom-meetings-2022.07.06" : {
    "settings" : {
      "index" : {
        "lifecycle" : {
          "name" : "zoom-meetings",
          "parse_origination_date" : "true",
          "origination_date" : "1657065600000"
        },
        "routing" : {
          "allocation" : {
            "include" : {
              "_tier_preference" : "data_content"
            }
          }
        },
        "number_of_shards" : "1",
        "provided_name" : "zoom-meetings-2022.07.06",
        "creation_date" : "1657078713263",
        "number_of_replicas" : "1",
        "uuid" : "tNTzffNlRm-Q2jIiP6c3wQ",
        "version" : {
          "created" : "7170499"
        }
      }
    }
  }
}

GET zoom-meetings-2022.07.06/_ilm/explain
{
  "indices" : {
    "zoom-meetings-2022.07.06" : {
      "index" : "zoom-meetings-2022.07.06",
      "managed" : true,
      "policy" : "zoom-meetings",
      "lifecycle_date_millis" : 1657065600000,
      "age" : "3.65h",
      "phase" : "delete",
      "phase_time_millis" : 1657078713380,
      "action" : "delete",
      "action_time_millis" : 1657078713380,
      "step" : "wait-for-shard-history-leases",
      "step_time_millis" : 1657078713380,
      "phase_execution" : {
        "policy" : "zoom-meetings",
        "phase_definition" : {
          "min_age" : "10m",
          "actions" : {
            "delete" : {
              "delete_searchable_snapshot" : true
            }
          }
        },
        "version" : 7,
        "modified_date_in_millis" : 1657076695678
      }
    }
  }
}

I have an index pattern as below.

PUT _index_template/zoom-meetings
{
  "index_patterns": ["zoom-meetings-*"],
  "template": {
    "settings": {
      "index.lifecycle.name": "zoom-meetings",
      "index.lifecycle.parse_origination_date": true
    }
  }
}

Is origination date parsed as long as the date format is included ?

Thanks,
Yu