Incoming Webhook duplicated message

Hello!

We're using Teams Incoming Webhook to send notifications to a channel when a ticket is opened in our workflow management tool and we're facing a strange behavior when posting to the webhook through Java's HttpClient (java.net.http).

Every time we send a notification, it arrives "duplicated". The first one arrives as expected and the card is filled with all the data needed. The second one arrives approximately one minute after the first one and there's almost no data in this second card.

In our implementation we have a serverless function (AWS Lambda) that handles the step of ticket opening process. After opening the ticket successfully, the notification is sent to Teams via the webhook.

According to our logs, the HTTP request that sends the notification is made only once, as expected. So, we're initially considering that there's nothing wrong with the HttpClient.

Note: when we post to the webhook using Postman or curl, everything works fine and the notification arrives with no duplication.

So, I ask: is there any way to debug the webhook?

Thanks!