sub-task workflow is wrong during move of parent

Project 1 has the issue types "Task" and "Sub-Task". Workflow scheme of project 1 (issue type --> workflow):
all unassigned types --> task_wf

Workflow scheme of project 2 (issue type --> workflow):
all unassigned types --> ea_wf
User Story --> us_wf
Sub-Task --> sub_task_wf

Now we move an issue of type "Task" with sub-tasks from project 1 to the type "User Story" in project 2. Important: The old status of the sub-task is not known in the new workflow.

When we have selected the target project and type ("project 2" and "User Story"), we get a screen where we can select the target statuses. There we read:

Type: Sub-Task (Workflow: task_wf --> ea_wf)

This is wrong, because it should be: task_wf --> sub_task_wf