I've just found this on one site. I have some (not all) cases of a given case type. There case status is set to a "closed" status. But the case does not have an end date.
I cannot find a way to update the case end date from the manage case screen.
This seems to effect cases where status was changed between July 17 and October 18 Cases amended before and since have an end date recorded
Cases with other closed statusses all have end dates as expected.
I guess I can find the related case status change activities, and then manually adjust the case end dates from cpanel (only a dozen or so cases affected).
Just left scratching my head, is all.