The overlay said "deleting 3 posts" something like that…. I know it can delete the thread but that didn't cross my mind…. Because prior to deleting those posts…. I 'moved' a few mosts from another thread which also included the opening post. That worked fine…. So I thought, if I delete the opening post, it'll just make the next users post as the opening post.
Forum stats are updated every 15 minutes and now it's been around 30 minutes. Stats are increasing as normal.