Adding mapping nodes affects target structure

Summary

Nodes added to mapping structure are showing up in the target segment

Content

I have setup a mapping view with 3 viewpoints(source, target and mapping).   When I add a node at the top of the mapping hierarchy to help organize the mappings the node gets added to the target structure as well. See attached picture. 

I have looked at the data chains but don't see anything that I could identify as the cause of this issue.