two urls for a discussion? and... can I move a question underneath a previous one?

First Question:
I just had a user place a discussion at the following url:
https://www.drcarney.com/talk/1636-introduction
It also shows up at this url:
https://www.drcarney.com/talk/1636-introduction-1
I am wondering why it is showing up at two urls. I did not find two discussion posts?

Second Question:
I am wondering if there is a way to move this particular discussion thread underneath an already existing thread?
At this page https://www.drcarney.com/talk you will see a thread called "Welcome and Introductions" and just below it there is another one called "Introduction".
It would be nice if I could put the most recent one called Introduction underneath the Welcomes and Introductions if this is a possibility?

Thanks, Sean