ListBackups since timestamp is null

Issues GraphQL
1

On 21.03 when querying the list of backups with:

query {
  listBackups(input: {
    location: "minio://127.0.0.1:9000/backups?secure=false"
    accessKey: "minioadmin"
    secretKey: "minioadmin"
  }) {
    backupId
    backupNum
    since
  }
}

The since timestamp is null:

{
  "data": {
    "listBackups": [
      {
        "backupId": "nifty_antonelli7",
        "backupNum": 1,
        "since": null
      },
      {
        "backupId": "nifty_antonelli7",
        "backupNum": 2,
        "since": null
      }
    ]
  }
}