Node widget form element disappears when clicking on "Add another item" and CCK fields are present on the parent content type

The node widget form element compeltely diappears from the form of the parent when clicking on "Add another item" and other CCK fields are enabled for the parent node.

Steps to reproduce:
- Add a node widget field to content type "Story", referencing content type "Page" and set the number of values to "unlimited"
- Create a story node and add several references to pages - this works
- Now add a simple text field to the content type "Story"
- Create another story node and try to add a second reference to a page by clicking on "Add another item"
- The node widget form element disappears completely!