Could not create index "system-logs" using dev tools

Hi Team,
I am using OS Version: 2.6.0

I was having index system_logs. Later I deleted the index system_logs and tried to create new index system-logs.
I am getting error as below:

put system-logs
{
  "error": {
    "root_cause": [
      {
        "type": "illegal_state_exception",
        "reason": "index, alias, and data stream names need to be unique, but the following duplicates were found [system-logs (alias of [system-logs/quK3mAfgRf6UvUqv-MNsgA]) conflicts with index]"
      }
    ],
    "type": "illegal_state_exception",
    "reason": "index, alias, and data stream names need to be unique, but the following duplicates were found [system-logs (alias of [system-logs/quK3mAfgRf6UvUqv-MNsgA]) conflicts with index]"
  },
  "status": 500
}

I checked there is no index already present OS with same name as per error, still I am getting error.

I am able to create index system_logs but not system-logs.
Pls let me know if I am missing something.

put system_logs
{
  "acknowledged": true,
  "shards_acknowledged": true,
  "index": "system_logs"
}

I think the reason is that the index name system-logs matches the index pattern defined in one of the index templates and the template defines an alias which is also named system-logs, so the error shows alias ... conflicts with index. You may need to remove alias part defined in the index template if you want to use system-logs as an index name.

By the way, GET _cat/templates API can show all of the index templates, you can check it.