You can also track story workflow state changes in Clubhouse.
The Story Timeline is located at the bottom of the story card and shows you who created the story and when and by whom the story state has changed.
By default, you will see the relative time of state changes (e.g. three months ago, two days ago) but hovering over the state change will give you a tooltip with absolute time (e.g. November 15, 2015, 5:55pm)