I am trying to update an entry in my DynamoDB Table via this piece of code below :

response = table.update_item(
                Key={
                    "id": id,  # Partition key
                    "timestamp": timestamp  # Sort key
                },
                UpdateExpression='SET formattedEventTimestamp = :val',
                ExpressionAttributeValues={':val': formatted_event_timestamp},
                ReturnValues="UPDATED_NEW",
            )
            print(response)

I am getting this output

{'Attributes': {'formattedEventTimestamp': '2024-04-17T07:18:23.884Z'}, 'ResponseMetadata': {'RequestId': 'P9V786Q1PA7UHCBSTGEKT1L7CRVV4KQNSO5AEMVJF66Q9ASUAAJG', 'HTTPStatusCode': 200, 'HTTPHeaders': {'server': 'Server', 'date': 'Wed, 24 Apr 2024 07:34:43 GMT', 'content-type': 'application/x-amz-json-1.0', 'content-length': '75', 'connection': 'keep-alive', 'x-amzn-requestid': 'P9V786Q1PA7UHCBSTGEKT1L7CRVV4KQNSO5AEMVJF66Q9ASUAAJG', 'x-amz-crc32': '3823649721'}, 'RetryAttempts': 0}}

Although when I check the entry corresponding to the id : 6bea0421-27f8-4e0c-a264-fcdd870078a2

I don’t find formattedEventTimestamp field added to it.

Here’s how the entry looks like

{
  "id": {
    "S": "6bea0421-27f8-4e0c-a264-fcdd870078a2"
  },
  "timestamp": {
    "N": "1712701935632"
  },
  "created_at": {
    "S": "2024-04-09T22:32:15.632Z"
  },
  "eventTimestamp": {
    "L": [
      {
        "N": "2024"
      },
      {
        "N": "4"
      },
      {
        "N": "9"
      },
      {
        "N": "22"
      },
      {
        "N": "32"
      },
      {
        "N": "15"
      },
      {
        "N": "384783746"
      }
    ]
  },
  "eventType": {
    "S": "BINDING_SUCCESS"
  },
  "pci": {
    "S": "5d215c89-8883-4de6-aec5-7ff60d519f68"
  }
}

How do I fix this issue ?