We have a situation in our team-managed project board where suddenly, right after completing a sprint and starting a new one, all previously completed sprints in our project are showing up in the project backlog again, with the historical dates still in there, but somehow seem to be registering as future sprints. We don't want to delete the sprints, as we're not sure what the implications are if we do, and we don't want to lose data or reports.
Anyone ever experienced something like this who can weigh in, so we can fix it?