How to avoid double writing when publishing RDS logs to Cloudwatch Logs.

I am publishing MySQL slow-query logs to CloudWatch Logs. When I look at CloudwatchLog, I see two logs with the same log. The same log is ingested at different times.

$ aws logs get-log-events --log-group-name /aws/rds/instance/db/slowquery --log-stream-name db
...
    "events": [
        {
            "ingestionTime": 1660018515125,
            "timestamp": 1660018510972,
            "message": "# Time: 2022-08-09T04:15:10.972506Z\n# User@Host: user[user] @  []  Id: 158209\n..."
        },
        {
            "ingestionTime": 1660021205551,
            "timestamp": 1660018510972,
            "message": "# Time: 2022-08-09T04:15:10.972506Z\n# User@Host: user[user] @  []  Id: 158209\n..."
        },

[5] pry(main)> Time.at 1660018515.125
=> 2022-08-09 13:15:15 +0900
[6] pry(main)> Time.at 1660021205.551
=> 2022-08-09 14:00:05 +0900

It sends once at 13:15 and again at 14:00 with the same log. I think RDS is probably sending twice from the same file, which setting should I change?