Pity there was no completion to this thread. I have the same issue in 3.0.9 but it was arrived at legitimately, if very stupidly.
A new poster made three identical posts. They were held in the waiting for approval status, but an admin went into the back end, and cleared all posts by that user, and this is shown in the admin logs. This has now left the offensive triangle on the forum, albeit only visible to admins, and when clicked shows three unapproved posts, but when any of these is selected, the reply is "You are not authorised to do this". I am a founder, cant get more authority. I don't want to have to go into SQL to fix this.
If the response here is that this has been fixed in a later version, I guess I will try once again to see if the webmaster will do that.