Issue Summary

After updating the project key on a project, it's now possible to delete the original project key and release it to be reused. (https://community.atlassian.com/t5/Jira-Cloud-Admins-articles/Announcing-the-ability-to-unlink-previously-used-project-keys/ba-p/2814789)

However, doing this breaks the project timeline view in team-managed software projects. It shows the generic "Timelines are designed for a single project" message seen in company-managed boards if the board filter includes multiple projects.

This happens because the board filter for the project isn't updated with the new key, it keeps the original key. Once the key is released, it doesn't redirect to that project anymore and the timeline isn't able to resolve the project.

Steps to Reproduce

1. Go to Project settings > Details on team-managed software project
2. Change the Project key to a new key
3. Under Previous project keys, delete the original project key and save the change.
4. Go to the Timeline view

Expected Results

The timeline continues to show issues from the current project normally

Actual Results

The timeline shows a message implying that the board filter includes multiple projects, and needs to be edited to only show one. (The filter for a team-managed project cannot be edited, and for new projects can't even be viewed.)

Workaround

Changing the project key back to the original key makes the timeline work normally again.
Additional info
To resolve board filter issues related to the Manage Sprints permission, revert to the original project key and then change it to the new project key you wish to use. This process will register the original project key as a previous project key, ensuring the board filter functions correctly once again.