Cards moved out of "Done" list don't become "unfinished" again

[beechnut]

In testing out a sprint, I moved cards into "Done" and back to their original to-do list again. However, while all the items are unfinished according to my board, only a few are unfinished according to the burndown.

[jwerba]

If you are still looking for this feature i invite you to take a look to https://github.com/jwerba/trello-burndown.