This seems to have just started happening when I installed v 3.1.2.
I go to the admin interface and click "Comments" to show all the comments. I pick one, and click Edit. I then click Update Comment and what I get is the Admin comments list with ONLY the comments attached to the article that the edited comment was on, not the list I was looking at.
This is like really annoying.
I tried to search to see if this issue had already been discussed, but it's not easy to find such things.