Hi Bill,
For each user task mendix creates an object of the entity WorkflowUserTask. Each object will has a unique ID and is committed to the Database.
In a Workflow the same UserTask can be triggered multiple times (with jumps etc). Each time a UserTask is triggered it creates a new instance of WorkflowUserTask. This explains why you have multiple different IDs for the same UserTask.
You can only figure out what the User Task id is after the WorkflowUserTask was instanciated. For this you can use the On created event and use the getGUID Action from the community commons to fetch the ID of the WorkflowUserTask