Is this a new feature? I discovered today that you can edit the text accompanying the "Possible Duplicate" box. This should be prevented unless you are a Moderator. It could result in the loss of key linked information. See this question (I rolled back the change). Doesn't seem right to me since you have to VOTE on what possible duplicates to include with the question. By editing, you are taking away that vote.
This is status-bydesign. It allows removing a link from the "possible duplicate" section in the event that there are several, but the question isn't a duplicate of one of them.