To reproduce the problem, create two field configurations (and field configuration schemes):

• one, where the description field uses "Default Text Renderer"
• one, where the description field uses "Wiki Style Renderer"

As next step create two projects:

• one, using the field configuration scheme with the "Default Text Renderer"
• one, using the field configuration scheme with the "Wiki Style Renderer"

Now create a Task issue in one of these project, and one ore two Sub-Tasks and type something in the Description field.

Now move the parrent Task issue to the other project.

You will see: The Sub-Tasks will have empty description fields!

Find out this problem in JIRA 5.0.6, and can reproduce it also in JIRA 5.1.8! (Out-Of-The-Box installation!)