When user clicks the button to delete a task, and confirms the deletion, we see a popup in the bottom right corner of the screen informing about the fact that the task got deleted successfully (see the first screen shot). At the same time, the task and the associated workspace are still there:
The popup disappears after a few seconds and the process of the deletion is only then reported in the task status. See the second screenshot.
The recommended behavior is to inform about the task deletion only AFTER it was deleted. Alternatively the popup might say something like "task deletion has started, and it may take a moment to be completed."