Program: 57888
Project: 57888
Buggy source:
@Override public boolean createRoadSouth(PlotArea plotArea,Plot plot){
  ClassicPlotWorld dpw=(ClassicPlotWorld)plotArea;
  Location pos1=getPlotBottomLocAbs(plotArea,plot.getId());
  Location pos2=getPlotTopLocAbs(plotArea,plot.getId());
  int sz=pos2.getZ() + 1;
  int ez=sz + dpw.ROAD_WIDTH - 1;
  int sx=pos1.getX() - 2;
  int ex=pos2.getX() + 2;
  LocalBlockQueue queue=plotArea.getQueue(false);
  int maxY=plotArea.getPlotManager().getWorldHeight();
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,Math.min(dpw.WALL_HEIGHT,dpw.ROAD_HEIGHT) + 1,sz),new Location(plotArea.worldname,ex - 1,Math.min(maxY,255),ez),PlotBlock.get((short)0,(byte)0));
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,0,sz),new Location(plotArea.worldname,ex - 1,0,ez),PlotBlock.get((short)7,(byte)0));
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,1,sz),new Location(plotArea.worldname,ex - 1,dpw.WALL_HEIGHT,sz),dpw.WALL_FILLING);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,dpw.WALL_HEIGHT + 1,sz),new Location(plotArea.worldname,ex - 1,dpw.WALL_HEIGHT + 1,sz),dpw.WALL_BLOCK);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,1,ez),new Location(plotArea.worldname,ex - 1,dpw.WALL_HEIGHT,ez),dpw.WALL_FILLING);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,dpw.WALL_HEIGHT + 1,ez),new Location(plotArea.worldname,ex - 1,dpw.WALL_HEIGHT + 1,ez),dpw.WALL_BLOCK);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,1,sz + 1),new Location(plotArea.worldname,ex - 1,dpw.ROAD_HEIGHT,ez - 1),dpw.ROAD_BLOCK);
  queue.enqueue();
  return true;
}

Fixed version (ground truth):
@Override public boolean createRoadSouth(PlotArea plotArea,Plot plot){
  ClassicPlotWorld dpw=(ClassicPlotWorld)plotArea;
  Location pos1=getPlotBottomLocAbs(plotArea,plot.getId());
  Location pos2=getPlotTopLocAbs(plotArea,plot.getId());
  int sz=pos2.getZ() + 1;
  int ez=sz + dpw.ROAD_WIDTH - 1;
  int sx=pos1.getX() - 2;
  int ex=pos2.getX() + 2;
  LocalBlockQueue queue=plotArea.getQueue(false);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,Math.min(dpw.WALL_HEIGHT,dpw.ROAD_HEIGHT) + 1,sz),new Location(plotArea.worldname,ex - 1,plotArea.getPlotManager().getWorldHeight(),ez),PlotBlock.get((short)0,(byte)0));
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,0,sz),new Location(plotArea.worldname,ex - 1,0,ez),PlotBlock.get((short)7,(byte)0));
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,1,sz),new Location(plotArea.worldname,ex - 1,dpw.WALL_HEIGHT,sz),dpw.WALL_FILLING);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,dpw.WALL_HEIGHT + 1,sz),new Location(plotArea.worldname,ex - 1,dpw.WALL_HEIGHT + 1,sz),dpw.WALL_BLOCK);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,1,ez),new Location(plotArea.worldname,ex - 1,dpw.WALL_HEIGHT,ez),dpw.WALL_FILLING);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,dpw.WALL_HEIGHT + 1,ez),new Location(plotArea.worldname,ex - 1,dpw.WALL_HEIGHT + 1,ez),dpw.WALL_BLOCK);
  queue.setCuboid(new Location(plotArea.worldname,sx + 1,1,sz + 1),new Location(plotArea.worldname,ex - 1,dpw.ROAD_HEIGHT,ez - 1),dpw.ROAD_BLOCK);
  queue.enqueue();
  return true;
}