I think it comes down to how the threads are named when they're first created. Reusing the same image doesn't seem to trigger it. As long as the title is unique enough it doesn't trigger the mislabeled crosspost behavior either, but editing a title after a post has already been marked as a crosspost doesn't fix it. I think just adding the xpac name should be enough? None of these posts are flagged as crossposts:

But the usual trading post thread did for whatever reason. Maybe the original title was too close?
