Issue Summary

Deleting a Sprint ( Non-Active) should move all its issues to the backlog but, it moves issues to the next available sprint instead of the backlog.

This is reproducible on Data Center: (yes) / (no) Yes

Steps to Reproduce

1. Create 3 sprints for example 
2. Assign a few issues to only one sprint ( Top one).
3. Try to delete the sprint(Non-active) then, we see all its issues are moving to next available sprint instead of going to Backlog.  

Expected Results

Should move issues to backlog

Actual Results

It is moving issues to next available sprint.

Workaround

When you are deleting the sprint make sure it is in (last in order) just above the backlog panel in the order like below. if you have more sprints then, click on the (...) of the sprint you can see an option to move the sprint back down option,, by using it get the sprint to the last in order so that when you delete the sprint it moves all issues to backlog instead of any random sprint.