What happens if you close a ticket as DONE by mistake, COMPLETE the sprint, and then realise your ticket wasn't done so you reset it as IN PROGRESS?
What seems to happen is that the velocity chart from the previous sprint doesn't update. That means potentially you are double counting the same ticket twice. Surely that is a bug?
I find it particularly troublesome if you look at the Sprint report and you see a ticket number, ticket description and status, with the status NOT being the current status (I.e. from this view it looks DONE, whereas when you click on it, you can see it is IN PROGRESS).
I am confident it didn't use to behave like this, so why did you change it?