When using a SharePoint List Items Event Wizard I receive an error when the event tries to update a document list item that is Checked Out. However, if I were to try to update the same list item using custom code (SharePoint API) it updates the item OK (no errors). Any ideas to this being a "designed feature" or bug?

By the way the exact error is: Server was unable to process request. ---> List Item not found: Item ID 3
---> Value does not fall within the expected range.