Webhook "TaskCreated" firing multiple times

I have a Folder Webhook that is set to fire only on the "TaskCreated" event. This Webhook adds a sequectial number prefix to the Task's title [via Azure function call]. It has worked flawlessly for a few weeks, but then we had a single Task that received multiple prefixes. We are stymied as to how a "TaskCreated" event was fired multiple times! It was our assumption that a Task may only be created one, single time. Can anyone explain how this could have happened?

Some other clue information we collected: The Task was originally created as a top-level Task, then later moved to another Folder as a Subtask.

Here is the definition of the Webhook in question...:

{
         "id": "IEADM7Z4JAABA2B3",
         "accountId": "IEADM7Z4",
         "folderId": "IEADM7Z4I4WX7P6P",
         "hookUrl": "https://hoodwrikeapi.azurewebsites.net/api/SetTaskTitle?code=AzurePrivateKey",
         "events": ["TaskCreated"],
         "recursive": false,
         "status": "Active"
 }