Program: 34009
Project: 34009
Buggy source:
/** 
 * Handles hitting minecarts or feeding animals
 * @param e
 */
@EventHandler(priority=EventPriority.LOWEST,ignoreCancelled=true) public void onPlayerHitEntity(PlayerInteractEntityEvent e){
  Player p=e.getPlayer();
  if (DEBUG) {
    plugin.getLogger().info("String_Node_Str" + e.getEventName());
  }
  if (!inWorld(p)) {
    return;
  }
  if (p.isOp() || VaultHelper.checkPerm(p,Settings.PERMPREFIX + "String_Node_Str")) {
    return;
  }
  if (p.getItemInHand() != null && p.getItemInHand().getType().equals(Material.LEASH)) {
    return;
  }
  Island island=plugin.getGrid().getProtectedIslandAt(e.getPlayer().getLocation());
  if (!plugin.getGrid().playerIsOnIsland(e.getPlayer())) {
    if (p.getItemInHand() != null && e.getRightClicked() instanceof Animals) {
      Material type=p.getItemInHand().getType();
      if (type == Material.EGG || type == Material.WHEAT || type == Material.CARROT_ITEM || type == Material.SEEDS) {
        if (island == null && !Settings.allowBreeding) {
          e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
          e.setCancelled(true);
          return;
        }
        if (island != null) {
          if (island.isSpawn()) {
            if (!Settings.allowSpawnBreeding) {
              e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
              e.setCancelled(true);
              return;
            }
          }
 else {
            if ((!island.getIgsFlag(Flags.allowBreeding) && !island.getMembers().contains(p.getUniqueId()))) {
              e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
              e.setCancelled(true);
              return;
            }
          }
        }
      }
    }
switch (e.getRightClicked().getType()) {
case HORSE:
      if (island == null && !Settings.allowHorseRiding) {
        e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
        e.setCancelled(true);
      }
    if (island != null && island.isSpawn()) {
      if (!Settings.allowSpawnHorseRiding) {
        e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
        e.setCancelled(true);
      }
    }
 else     if (island != null && !island.getIgsFlag(Flags.allowHorseRiding)) {
      e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
      e.setCancelled(true);
    }
  break;
case ITEM_FRAME:
case MINECART_CHEST:
case MINECART_FURNACE:
case MINECART_HOPPER:
if (island == null && !Settings.allowChestAccess) {
  e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
  e.setCancelled(true);
}
if (island != null) {
if (island.isSpawn()) {
  if (!Settings.allowSpawnChestAccess) {
    e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
    e.setCancelled(true);
  }
}
 else if (!island.getIgsFlag(Flags.allowChestAccess)) {
  e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
  e.setCancelled(true);
}
}
break;
default :
break;
}
}
}

Fixed version (ground truth):
/** 
 * Handles hitting minecarts or feeding animals
 * @param e
 */
@EventHandler(priority=EventPriority.LOWEST,ignoreCancelled=true) public void onPlayerHitEntity(PlayerInteractEntityEvent e){
  Player p=e.getPlayer();
  if (DEBUG) {
    plugin.getLogger().info("String_Node_Str" + e.getEventName());
  }
  if (!inWorld(p)) {
    return;
  }
  if (p.isOp() || VaultHelper.checkPerm(p,Settings.PERMPREFIX + "String_Node_Str")) {
    return;
  }
  if (p.getItemInHand() != null && p.getItemInHand().getType().equals(Material.LEASH)) {
    return;
  }
  Island island=plugin.getGrid().getProtectedIslandAt(e.getPlayer().getLocation());
  if (!plugin.getGrid().playerIsOnIsland(e.getPlayer())) {
    if (p.getItemInHand() != null && e.getRightClicked() instanceof Animals) {
      Material type=p.getItemInHand().getType();
      if (type == Material.EGG || type == Material.WHEAT || type == Material.CARROT_ITEM || type == Material.SEEDS) {
        if (island == null && !Settings.allowBreeding) {
          e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
          e.setCancelled(true);
          return;
        }
        if (island != null) {
          if (island.isSpawn()) {
            if (!Settings.allowSpawnBreeding) {
              e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
              e.setCancelled(true);
              return;
            }
          }
 else {
            if ((!island.getIgsFlag(Flags.allowBreeding) && !island.getMembers().contains(p.getUniqueId()))) {
              e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
              e.setCancelled(true);
              return;
            }
          }
        }
      }
    }
switch (e.getRightClicked().getType()) {
case HORSE:
      if (island == null && !Settings.allowHorseRiding) {
        e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
        e.setCancelled(true);
      }
    if (island != null && island.isSpawn()) {
      if (!Settings.allowSpawnHorseRiding) {
        e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
        e.setCancelled(true);
      }
    }
 else     if (island != null && !island.getIgsFlag(Flags.allowHorseRiding)) {
      e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
      e.setCancelled(true);
    }
  break;
case ITEM_FRAME:
if (island == null && !Settings.allowPlaceBlocks) {
  e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
  e.setCancelled(true);
}
if (island != null) {
if (island.isSpawn()) {
  if (!Settings.allowSpawnPlaceBlocks) {
    e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
    e.setCancelled(true);
  }
}
 else if (!island.getIgsFlag(Flags.allowPlaceBlocks)) {
  e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
  e.setCancelled(true);
}
}
break;
case MINECART_CHEST:
case MINECART_FURNACE:
case MINECART_HOPPER:
if (island == null && !Settings.allowChestAccess) {
e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
e.setCancelled(true);
}
if (island != null) {
if (island.isSpawn()) {
if (!Settings.allowSpawnChestAccess) {
e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
e.setCancelled(true);
}
}
 else if (!island.getIgsFlag(Flags.allowChestAccess)) {
e.getPlayer().sendMessage(ChatColor.RED + plugin.myLocale(e.getPlayer().getUniqueId()).islandProtected);
e.setCancelled(true);
}
}
break;
default :
break;
}
}
}