Unable to add issues to sprint on Next-gen projects

Issue Summary

Unable to add issues to sprint on Next-gen projects. This happens to instances that previously had turned on Sprint featured, but then turned it off again. An upgrade task ran on their instance, and then they turned Sprints back on.

Environment

• Jira Software Cloud

Steps to Reproduce

n/a

Expected Results

All issues are added to the sprint.

Actual Results

Issues reverting back to the backlog after a page refresh.

Notes

Workaround

1. Go to the Project Settings >  Issue types and find the affected issue type.
2. Change the order of any 2 fields and click Save.
3. Revert the ordering and click Save.