We have a sprint burndown chart for a recent and closed sprint which does not burn all the way to the end of the period - it stops/has a gap with a day to go and the graph doesn't touch the rightmost side.
We had a lot of issues marked as done and some scope changes. We also had some incomplete issues which were moved to the next (current) sprint. Finally, some issues were removed from the sprint, all of which have now been marked as done except one (an epic, which stretches across multiple sprints and should not have been included in this sprint).
Do you know why the chart stops, how to fix it and why it happened/how to prevent it from happening in the future
Image link (trimmed) here: https://img42.com/EyXrP