Closed or resolved issues appear in a scrum board backlog in Jira server
Platform Notice: Cloud, Server, and Data Center - This article applies equally to all platforms.
Note: This KB article applies to older versions of Jira 6 and early 7 versions. In Jira 8, this KB no longer applies. In the recent versions, even if you have the Closed issues mapped to the last column of the board and the resolution field is set, they are still gets listed in the backlog with a strike-through, this is the default behavior. A workaround would be to create a new board quick filter name it such as "Unresolved issues" to only list/filter out the issues which are yet to be resolved.
Steps to create the quick filter: click on Board > Scrum Board > Configure Board> quick filter.
Suddenly the closed issues from the project are appearing in the backlog of the Scrum board.
JIRA Software does not display issues from the last column of the Scrum board configuration in the backlog section. If your closed issues are not mapped to the last column of the board, then they would be displayed in the backlog.
For example, in this configuration:
In order to fix the problem here, we would need to configure the 'Done' column as the last column from the board column configuration. Once we do that, the closed issues would stop appearing in the backlog of the Scrum board.