Session timeout while bulk editing sub-tasks

Summary

 A session timeout error is shown when bulk editing sub-tasks. It happens only when selecting bulk edit by clicking on the (...) button above the sub-tasks list inside a parent issue (see screenshot below).

This also happens when there are no sub-tasks.

Environment

There is no specific environment

Steps to Reproduce

1. Go to an issue with sub-tasks
2. Above the list of sub-tasks click on (...) > Bulk Operation
3. Select all sub-tasks and click on next

Expected Results

The page to select the bulk operation should appear

Actual Results

This one appears on Jira log

/secure/views/bulkedit/BulkMigrateSetFields.jspa [c.a.j.w.a.issue.bulkedit.BulkMigrate] Bulk edit bean unexpectedly null. Perhaps session was lost (e.g. when URL used is different to base URL in General Configuration)?

Notes

(Optional - If Necessary)

Potential Workaround

1. Go to Issues > Search for issues
2. Search for parent issue (parent = TEST-1), it’ll list all sub-tasks
3. Click Tools > Bulk Change > all x issue(s)