ILM phase don't delete indexes (els 7.9)

[zakabluk (Andrei Zakabluk)]

My ILM policy

PUT _ilm/policy/delete-after-7-days
{
  "policy": {
    "phases": {
      "hot": {
        "min_age": "0ms",
        "actions": {
          "set_priority": {
            "priority": 100
          }
        }
      },
      "delete": {
        "min_age": "7d",
        "actions": {
          "delete": {
            "delete_searchable_snapshot": true
          }

GET .ds-logstash-f-lb-2021.01.29-000001/_ilm/explain

  "indices" : {
    ".ds-logstash-fornex-lb-2021.01.29-000001" : {
      "index" : ".ds-logstash-f-lb-2021.01.29-000001",
      "managed" : true,
      "policy" : "delete-after-7-days",
      "lifecycle_date_millis" : 1611878426807,
      "age" : "11.38d",
      "phase" : "delete",
      "phase_time_millis" : 1612483233516,
      "action" : "delete",
      "action_time_millis" : 1612483233516,
      "step" : "delete",
      "step_time_millis" : 1612483781849,
      "phase_execution" : {
        "policy" : "delete-after-7-days",
        "phase_definition" : {
          "min_age" : "7d",
          "actions" : {
            "delete" : {
              "delete_searchable_snapshot" : true
            }
          }
        },
        "version" : 4,
        "modified_date_in_millis" : 1612254154538
      }

index not deleted today is 2021 feb 09. I don't understand why

[zakabluk (Andrei Zakabluk)]

In logs I see error

"stacktrace": ["java.lang.IllegalStateException: index [.ds-logstash-f-lb-2021.01.29-000001] is the write index for data stream [logstash-f-lb-2021.01.29]. stopping execution of lifecycle [delete-after-7-days] as a data stream's write index cannot be deleted. manually rolling over the index will resume the execution of the policy as the index will not be the data stream's write index anymore",
"at