Cognito presignup trigger fires twice or multiple time.

Hi, I'm using an AWS Lambda function. Once any request from APP to Cognito to signUp users. Then I have set the Pre sign-up trigger to send OTP to the customer and return the event to Cognito. It happens sometime in the request, not all the time. it will trigger 3 times sometime and most of the time twice As per this link https://docs.aws.amazon.com/cognito/latest/developerguide/cognito-user-identity-pools-working-with-aws-lambda-triggers.html#cognito-user-identity-pools-working-with-aws-lambda-triggers-using-lambda Important Amazon Cognito invokes Lambda functions synchronously. When called, your Lambda function must respond within 5 seconds. If it does not, Amazon Cognito retries the call. After 3 unsuccessful attempts, the function times out. This 5-second timeout value cannot be changed.