I took a backup of S3 with AWS Backup, but "BackupSizeBytes" becomes 0 with the "list-recovery-points-by-resource" command.

[Kobayashi-Riku0226]

Hello.

As the title suggests, I took a backup of S3 using AWS Backup.
I ran the "list-recovery-points-by-backup-vault" command to check the backup size, but "BackupSizeBytes" was 0.
Is this the right move?
If it's not correct, why is it 0?

aws backup list-recovery-points-by-resource --resource-arn arn:aws:s3:::s3-bucket-name

Below is the response.

{
    "RecoveryPoints": [
        {
            "RecoveryPointArn": "arn:aws:backup:ap-northeast-1:1111111111111:recovery-point:s3-bucket-name-20240622040825-111111111",
            "CreationDate": "2024-06-22T04:08:25.206000+00:00",
            "Status": "COMPLETED",
            "EncryptionKeyArn": "arn:aws:kms:ap-northeast-1:1111111111111:key/yyyyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy",
            "BackupSizeBytes": 0,
            "BackupVaultName": "Default",
            "IsParent": false,
            "ResourceName": "s3-bucket-name",
            "VaultType": "BACKUP_VAULT"
        }
    ]
}