As an administrator i cannot assign confluence tasks to one specific user on my team, I can choose pratically anyone else in my organization except @userwho is in the Devleoper Group as the others in the organization. I reviewed permissions and it seems the user has no different from others in the confluence project.
In tern, the user in question has full access to the confluence projects and is free to create and interact with content content and other users but he also cannot assign me confluence tasks or add me to watch.
Thanks