Ok I believe I have figured it out. Since been using the beta version and now moved to the ardent debian version.
After installation, when I moved to the ament tutorial:
wget https://raw.githubusercontent.com/ros2/ros2/master/ros2.repos
vcs import ~/ros2_ws/src < ros2.repos
I ran those again. That is why it was creating duplicate probably. Just realised it is clearly mentioned there:
To start off we need to setup an underlay without any of ROS2 installed.
My apologies @dirk-thomas and that is great that I don’t need to go through the 2 hours of build and test time to set up my ros2.