We face an issue from a few weeks(jira software datacenter). We have an active sprint (e.g. Sprint23) and a few future sprints created in a backlog (e.g. Sprint24, Sprint25). When we close the sprint we want to move not done items to another sprint (e.g Sprint24). We select that sprint during current sprint closure. What is suprising some of not finished items in the sprint (Sprint23) are moved to selected sprint (Sprint24) but also some of not finished items are not moved to Sprint24 (the field sprint is not updated for them). It was a few times what happened when we were closing Sprint(n) and moving not finished items to Sprint(n+1) and some not finished items were moved and some not.
Do you have any idea what could be the reason and how to fix that?
Is it a bug on jira side, have you ever experience that?