Doh!

Found a small bug with my implementation, will fix later today or during the weekend.

We create the topic, immediately after we create the automatic "watchers", then we call the notification routine to create emails...

In theory you should receive a forum watch notification for the new topic, but the routine is the same for new topic and new replies. So whoever is in the automatic topic watch gets a notification of replies - even with no replies.

I know this is happening, where it is happening, and will fix later.