Issue Summary

Using the Move feature to change issue type when there is an empty required field returns error 500.

Steps to Reproduce

1. Ensure that there are at least two issue types at level 1 in Hierarchy Configuration (Settings -> Issues -> Issue Type hierarchy).
2. Create an issue with one of the issue types at level 1.
3. Add a child issue for it.
4. Add an optional custom field to the child issue's Field Configuration. Ensure that the field's value in the child issue is empty.
5. Make this field required via Field Configuration.
6. Using the "Move" dialog, change the parent issue's issue type to the other issue type at level 1. If the current issue type is the "managed system epic type" (the one used in the Epics panel, Epic reports, and so on), then change it to any other issue type at level 1. Otherwise, change it to the "managed system epic type".

Expected Results

issue type changes.

Actual Results

Error 500.

Workaround

Open the child issue(s), and fill in the values for all the required fields. After that, changing the parent's issue type will work.