My project is to send an email notification to the author whenever a new post is published, so I set a webhook for post published, a REST API on AWS API Gateway that used Lambda proxy and a Lambda function to send emails. The problem is that API Gateway was invoked multiple times for the same published post, usually 3 times within a few seconds. I also checked Cloudwatch logs, making sure the invocations were coming from the same webhook trigger. What is the possible cause of this? Any help is appriciated!