It turns out that child agent management has had a bug for a while: there was an inconsistency in the scope between opening and closing child agents in neighboring regions. For opening (in EnableChildAgents), the region's DrawDistance was being used; for closing (in IsOUtsideView) , the viewer's (SP) DrawDistance was being used. This fixes this inconsistency, therefore eliminating bugs observed in TPs between, at least, neighboring varregions.