When using Appit for SharePoint to copy list items from one list to another list, the Copy List Item event will only copy the Title property of the list item when the Content Type for the list is enabled.
This usually happens when the Content Type for the list is enabled.
The issue has been identified as a known issue with current version of Appit (1.5 Update 3). The issue will be resolved in a future release. As a workaround, you could use the Create List Item event instead.