CloudTrail event too large

I sending CloudTrail API event for event source ec2 to CW Events. Following is the Event Pattern configured in EventBridge

{
  "detail": {
    "eventName": ["RunInstances"]
    "eventSource": ["ec2.amazonaws.com"]
  },
  "detail-type": ["AWS API Call via CloudTrail"]
  "source": ["aws.ec2"]
}

I am not getting complete event but the following message

  {
      "omitted": true, 
      "originalSize": 109435, 
      "reason": "responseElements too large"
  }

If I check Quotas in CloudTrail user guide, it is mentioned that events can have a max size of 256 KB. The original size mentioned above is less than that, could anyone help me with understanding why I am not getting the complete event?

Thanks!