All of the feeds default to some sort of random sort after reset. For a new visitor it looks like hubski is totally dead and there is one post from today than one from 42 days ago than one from 3 years ago. Not good for new user retention
This might be the same as what you're describing. I'm not sure, so I'll add to your comment. Whenever there's a bug fix or a change in the database, the chatter has a chunk of comments that are exactly the same comments from long ago at different times placed within the new comments. I have come to recognize the comments, so I don't pay much attention to them, but when it first happened, I was pretty confused. Someone made a thread about it and mk noted that it would be fixed. I'm adding my comment here in case it was thought to be fixed but got overlooked. Thanks rob05c, for all your hard work.