The epic completion date is hard to predict because the team adds new stories throughout the epic. This means that the scope of the epic is not fixed and can change over time. The Epic Report shows the progress of an epic by comparing the estimated amount of work to the completed work. The report also shows a projected completion date based on the team’saverage velocity. However, if the team keeps adding new stories to the epic, the estimated amount of work will increase and the projected completion date will be pushed further. This makes it difficult to plan and deliver the epic within a certain timeframe. References: Managing Jira Projects Data Center and Server: Certification Bundle, Epic Report