Duplicate Pre-processing 
If you select duplicate on a workflow that is still in the "New State" with no steps created and is still RAW,  the duplicate will be a separate file. This is suggested for creating a backup file should you need to redo the editing.

Duplicate Post-processing
When a workflow has gone through segmentation and builder, but not yet published, you still can select Duplicate. This creates a mirror image of the original, any changes made to the copy will also be made to the original while in this state

This is due to the fact that the chapters are now created and any change to a chapter cascades to all workflows where that chapter is present.

Tips: You can use the reset workflow option at any time along the editing process of the workflow to reset back to the original state. If so, you have an option to keep a copy of the original before DeepHow processes the copy.