Unable to remove link only on part of one anchor

I work for a french news website and we have been using CKeditor for a few month.

I have received a request from several users about the remove link feature. If user makes a partial selection of the link's anchor and then clicks on the the "remove link" icon, the whole link is usually deleted. But sometimes, the link is removed only on the selected characters, which is (from our point of view) a better behavior.

Not sure how to reproduce this problem though, but it can also been experienced on the demo of CKeditor : http://ckeditor.com/demo