Rollover issues from previous sprint not showing on burndown reports?

[Adam Purcell]

Every sprint is the same. We complete a bunch of tickets and there's a few left open at the end. Every week we close the sprint and incomplete issues roll over to the next sprint. We start the next sprint and all issues both new for that sprint and roll over appear on the board as well as in my burnup and burndown reports. All working well. 

However, this week something changed (although I changed nothing!) A bunch of issues rolled over to this week's sprint to join some new ones. But, even though they appear on the board, they are all missing from the burnup/down reports. Should say about 100 story points but only says 53. I had to look closely but it's just the rollovers that won't show up. I can remove one from the sprint and add it back again, or change it's story points but no change at all. The graphs are simply not picking them up.

Any ideas? How can this suddenly change without anything having changed?