Hi,
Are your buildings being added to a Forest Set automatically from a layer? If so, there is a known limitation with this configuration (this is due to limitations with Max that we can't circumvent at this point). If that's the case, you'll need to rebuild the Forest Object after you've moved the building for the scatter to update. You can do this from the Display rollout, or using a button at the top of the Forest Pack lister.
If that's not the issue, please feel free to send us a simplified scene reproducing the problem to helpdesk@itoosoft.com.
Many thanks,
Paul