Program: 57918
Project: 57918
Buggy source:
@EventHandler(priority=EventPriority.LOWEST) public void blockDestroy(BlockBreakEvent event){
  Player player=event.getPlayer();
  Location loc=BukkitUtil.getLocation(event.getBlock().getLocation());
  PlotArea area=loc.getPlotArea();
  if (area == null) {
    return;
  }
  Plot plot=area.getPlotAbs(loc);
  if (plot != null) {
    PlotPlayer pp=BukkitUtil.getPlayer(player);
    if (event.getBlock().getY() == 0) {
      if (!Permissions.hasPermission(pp,C.PERMISSION_ADMIN_DESTROY_GROUNDLEVEL)) {
        MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_DESTROY_GROUNDLEVEL);
        event.setCancelled(true);
        return;
      }
    }
    if (!plot.hasOwner()) {
      if (Permissions.hasPermission(pp,C.PERMISSION_ADMIN_DESTROY_UNOWNED)) {
        return;
      }
      MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_DESTROY_UNOWNED);
      event.setCancelled(true);
      return;
    }
 else     if (!plot.isAdded(pp.getUUID())) {
      Optional<HashSet<PlotBlock>> destroy=plot.getFlag(Flags.BREAK);
      Block block=event.getBlock();
      if (destroy.isPresent() && destroy.get().contains(new PlotBlock((short)block.getTypeId(),block.getData()))) {
        return;
      }
      if (Permissions.hasPermission(pp,C.PERMISSION_ADMIN_DESTROY_OTHER)) {
        return;
      }
      MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_DESTROY_OTHER);
      event.setCancelled(true);
    }
 else     if (Settings.DONE_RESTRICTS_BUILDING && plot.getFlags().containsKey(Flags.DONE)) {
      if (!Permissions.hasPermission(pp,C.PERMISSION_ADMIN_BUILD_OTHER)) {
        MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_BUILD_OTHER);
        event.setCancelled(true);
        return;
      }
    }
    return;
  }
  PlotPlayer pp=BukkitUtil.getPlayer(player);
  if (Permissions.hasPermission(pp,C.PERMISSION_ADMIN_DESTROY_ROAD)) {
    return;
  }
  if (PS.get().worldedit != null && pp.getAttribute("String_Node_Str")) {
    if (player.getItemInHand().getTypeId() == PS.get().worldedit.getConfiguration().wandItem) {
      return;
    }
  }
  MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_DESTROY_ROAD);
  event.setCancelled(true);
}

Fixed version (ground truth):
@EventHandler(priority=EventPriority.LOWEST) public void blockDestroy(BlockBreakEvent event){
  Player player=event.getPlayer();
  Location loc=BukkitUtil.getLocation(event.getBlock().getLocation());
  PlotArea area=loc.getPlotArea();
  if (area == null) {
    return;
  }
  Plot plot=area.getPlotAbs(loc);
  if (plot != null) {
    PlotPlayer pp=BukkitUtil.getPlayer(player);
    if (event.getBlock().getY() == 0) {
      if (!Permissions.hasPermission(pp,C.PERMISSION_ADMIN_DESTROY_GROUNDLEVEL)) {
        MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_DESTROY_GROUNDLEVEL);
        event.setCancelled(true);
        return;
      }
    }
    if (!plot.hasOwner()) {
      if (Permissions.hasPermission(pp,C.PERMISSION_ADMIN_DESTROY_UNOWNED)) {
        return;
      }
      MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_DESTROY_UNOWNED);
      event.setCancelled(true);
      return;
    }
    if (!plot.isAdded(pp.getUUID())) {
      Optional<HashSet<PlotBlock>> destroy=plot.getFlag(Flags.BREAK);
      Block block=event.getBlock();
      if (destroy.isPresent() && destroy.get().contains(new PlotBlock((short)block.getTypeId(),block.getData()))) {
        return;
      }
      if (Permissions.hasPermission(pp,C.PERMISSION_ADMIN_DESTROY_OTHER)) {
        return;
      }
      MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_DESTROY_OTHER);
      event.setCancelled(true);
    }
 else     if (Settings.DONE_RESTRICTS_BUILDING && plot.getFlags().containsKey(Flags.DONE)) {
      if (!Permissions.hasPermission(pp,C.PERMISSION_ADMIN_BUILD_OTHER)) {
        MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_BUILD_OTHER);
        event.setCancelled(true);
        return;
      }
    }
    return;
  }
  PlotPlayer pp=BukkitUtil.getPlayer(player);
  if (Permissions.hasPermission(pp,C.PERMISSION_ADMIN_DESTROY_ROAD)) {
    return;
  }
  if (PS.get().worldedit != null && pp.getAttribute("String_Node_Str")) {
    if (player.getItemInHand().getTypeId() == PS.get().worldedit.getConfiguration().wandItem) {
      return;
    }
  }
  MainUtil.sendMessage(pp,C.NO_PERMISSION_EVENT,C.PERMISSION_ADMIN_DESTROY_ROAD);
  event.setCancelled(true);
}