I've tried everything in the sun and cannot for the life of me get the Create Subtask post-function to work using Script Runner.
The user executing the transition has permission to create issues.
The target subtask is a valid issuetype in the project.
The workflow it's using is the classic workflow.
The field configuration scheme for the issue type is also the default and has no restrictions.
There's nothing special in the actual post function itself, just a 'Create Subtask' task.
I looked in atlassian-JIRA and could not find anything helpful other than:
2015-09-30 09:52:15,368 http-bio-443-exec-24914 ERROR awhite 592x7901709x3 19ulta1 172.27.88.168 /secure/CommentAssignIssue.jspa [scriptrunner.jira.workflow.ScriptWorkflowFunction] Script function failed on issue: HREO-15, actionId: 51, file: null
Any ideas?