We have added the ability for users to edit the task completed date. Previously the task completed date is the date that the user ticked the task as complete in Cascade. However this can sometimes be inaccurate.
To make the task completion status (x days ahead/behind schedule) more accurate, you can now edit your task completion date. Go the the goal hub of the goal that your task is attached to, click on 'Tasks' card. Then on your completed task card, an edit icon will show up if you hover over completion date. Click on the edit icon and select the actual completion date in the calendar.