Program: 41981
Project: 41981
Buggy source:
@SuppressWarnings("String_Node_Str") @EventHandler(priority=EventPriority.HIGH,ignoreCancelled=true) public void onPlayerInteract(PlayerInteractEvent event){
  IPlayer player=plugin.wrapPlayer(event.getPlayer());
  ILocation location=new ILocation(player.getWorld(),BukkitUtil.locationToVector(event.getClickedBlock().getLocation()));
  if (manager.isPlotWorld(location)) {
    Plot plot=manager.getPlot(location);
    boolean canBuild=!player.hasPermission(PermissionNames.ADMIN_BUILDANYWHERE);
    PlotMapInfo pmi=manager.getMap(location);
    if (event.isBlockInHand() && event.getAction() == Action.RIGHT_CLICK_BLOCK) {
      if (plot == null || !plot.isAllowed(player.getUniqueId())) {
        if (canBuild) {
          player.sendMessage(api.C("String_Node_Str"));
          event.setCancelled(true);
        }
      }
 else {
        plot.resetExpire(pmi.getDaysToExpiration());
      }
    }
 else {
      boolean blocked=false;
      if (pmi.isProtectedBlock(event.getClickedBlock().getTypeId()) && !player.hasPermission("String_Node_Str" + event.getClickedBlock().getTypeId())) {
        blocked=true;
      }
      ItemStack item=event.getItem();
      if (event.getAction() == Action.RIGHT_CLICK_BLOCK && item != null) {
        int itemId=item.getType().getId();
        byte itemData=item.getData().getData();
        if ((pmi.isPreventedItem(String.valueOf(itemId)) || pmi.isPreventedItem(itemId + "String_Node_Str" + itemData)) && !player.hasPermission("String_Node_Str" + itemId) || item.getType().equals(Material.MONSTER_EGG)) {
          blocked=true;
        }
      }
      if (blocked && (plot == null || !plot.isAllowed(player.getUniqueId())) && canBuild) {
        player.sendMessage(api.C("String_Node_Str"));
        event.setCancelled(true);
      }
    }
  }
}

Fixed version (ground truth):
@SuppressWarnings("String_Node_Str") @EventHandler(priority=EventPriority.HIGH,ignoreCancelled=true) public void onPlayerInteract(PlayerInteractEvent event){
  IPlayer player=plugin.wrapPlayer(event.getPlayer());
  Location location=new Location(player.getWorld(),BukkitUtil.locationToVector(event.getClickedBlock().getLocation()));
  if (manager.isPlotWorld(location)) {
    Plot plot=manager.getPlot(location);
    boolean canBuild=!player.hasPermission(PermissionNames.ADMIN_BUILDANYWHERE);
    PlotMapInfo pmi=manager.getMap(location);
    if (event.isBlockInHand() && event.getAction() == Action.RIGHT_CLICK_BLOCK) {
      if (plot == null || !plot.isAllowed(player.getUniqueId())) {
        if (canBuild) {
          player.sendMessage(api.C("String_Node_Str"));
          event.setCancelled(true);
        }
      }
 else {
        plot.resetExpire(pmi.getDaysToExpiration());
      }
    }
 else {
      boolean blocked=false;
      if (pmi.isProtectedBlock(event.getClickedBlock().getTypeId()) && !player.hasPermission("String_Node_Str" + event.getClickedBlock().getTypeId())) {
        blocked=true;
      }
      ItemStack item=event.getItem();
      if (event.getAction() == Action.RIGHT_CLICK_BLOCK && item != null) {
        int itemId=item.getType().getId();
        byte itemData=item.getData().getData();
        if ((pmi.isPreventedItem(String.valueOf(itemId)) || pmi.isPreventedItem(itemId + "String_Node_Str" + itemData)) && !player.hasPermission("String_Node_Str" + itemId) || item.getType().equals(Material.MONSTER_EGG)) {
          blocked=true;
        }
      }
      if (blocked && (plot == null || !plot.isAllowed(player.getUniqueId())) && canBuild) {
        player.sendMessage(api.C("String_Node_Str"));
        event.setCancelled(true);
      }
    }
  }
}