Task List in the UWL Is Not Updated 
Symptom
The task list in the UWL is not updated after a task is completed, approved, or rejected.
Reason
When a task is executed in the UWL, this execution runs out of the UWL context. The UWL is not aware of the result of the work item execution. This means that the UWL does not know, whether the task is completed after the execution. So the task is not removed from the task list in the UWL after it has been completed. It only disappears from the task list after the user uses the Refresh function that retrieves the inbox of the logged on user from the back end.
Solution
You can solve the problem with one of the following procedures:
Using the Optimized Delta Pull
Use and if necessary configure the optimized delta pull. The optimized delta pull retrieves the recently changed items from the back end provider based on timestamp information.
More information: Enabling Delta Pull Mechanism
Refreshing with Hidden iView
Add a hidden iView on the page that raises the refreshUwlBackend event. This is the same event that is triggered when users manually choose the Refresh function. If the user returns to the task list after a task has been completed, approved, or rejected in another window, the refresh is automatically done by the iView.
Note
This iView and within the iView the refresh is called every time the user opens the UWL.