When I've flagged questions as potential duplicates in the past, a comment was auto-generated to that effect. When I just did the same thing, no such comment was generated (How to structure Util classes in RoR).
The only circumstance I know that was different was that I'd just "answered" the question and had my answer turned into a comment as being "trivial". I then deleted the comment before flagging the question, on the assumption that a flag-related comment would be auto-generated.
Anyone know what's up? Was the system behavior recently changed?