Issue Summary

When moving an issue with 11 sub-tasks, only 10 sub-tasks will be affected, leaving 1 sub-task untouched.
The problem also occurs when there are 21, 31... sub-tasks, which would leave 1 sub-task behind.

Steps to Reproduce

1. Install a vanilla instance of Jira Data Center.
   • This was validated with JSW DC versions 9.4.29, 9.12.16 and 10.3.0.
2. Create two sample software projects (i.e. SCRUM1 and KANBAN1).
3. On one of the projects (SCRUM1), create a task and add 11 sub-tasks to it.
   
4. On the task, click on More > Move to move the task and its sub-tasks to the other project (KANBAN1).
   

Expected Results

In total 12 issues are moved from project SCRUM1 to KANBAN1, 1 task and 11 sub-tasks.

Actual Results

In total 11 issues are moved from project SCRUM1 to KANBAN1, 1 task and 10 sub-tasks.
1 sub-task is left behind and not moved.

Workaround

There's currently no workaround to prevent this bug.
To identify affected sub-tasks the administrator may run the following SQL query.

SELECT
  p.pkey ||'-'|| jid.issuenum AS "Sub-task key"
FROM issuelink il
JOIN jiraissue jis
  ON jis.id = il.source
JOIN jiraissue jid
  ON jid.id = il.destination
JOIN project p
  ON p.id = jid.project
WHERE il.linktype = (select id from issuelinktype where linkname = 'jira_subtask_link')
AND jis.project <> jid.project;

Running the "move" operation on the parent again would fix the sub-task that was still on the previous project.