Program: 178716
Project: 178716
Buggy source:
@EventHandler() public void onBlockBreak(BlockBreakEvent event){
  Block block=event.getBlock();
  V10Location loc=new V10Location(block);
  Portal portal=plugin.portalManager.borderBlocks.get(loc);
  if (portal == null)   portal=plugin.portalManager.behindBlocks.get(loc);
  if (portal != null) {
    portal.delete();
    event.setCancelled(true);
    return;
  }
  portal=plugin.portalManager.insideBlocks.get(loc);
  if (portal != null) {
    if (portal.transmitter && block.getType() == Material.REDSTONE_TORCH_ON)     event.setCancelled(true);
    return;
  }
  Grill grill=plugin.grillManager.insideBlocks.get(loc);
  if (grill != null)   event.setCancelled(true);
  V10Location vb=new V10Location(block);
  Bridge bridge=plugin.funnelBridgeManager.bridgeBlocks.get(vb);
  if (bridge != null) {
    event.setCancelled(true);
    return;
  }
  bridge=plugin.funnelBridgeManager.bridgeMachineBlocks.get(vb);
  if (bridge != null) {
    if (plugin.hasPermission(event.getPlayer(),plugin.PERM_DELETE_BRIDGE))     bridge.delete();
 else     event.setCancelled(true);
    return;
  }
  plugin.funnelBridgeManager.updateBridge(loc);
  Region region=plugin.regionManager.getRegion(loc);
  if (plugin.blockUtil.compareBlockToString(block,region.getString(RegionSetting.GRILL_MATERIAL))) {
    grill=plugin.grillManager.borderBlocks.get(loc);
    if (grill == null || !plugin.hasPermission(event.getPlayer(),plugin.PERM_DELETE_GRILL))     return;
    grill.delete();
  }
  Material type=block.getType();
  if (type == Material.REDSTONE_WIRE && region.getBoolean(RegionSetting.ENABLE_REDSTONE_TRANSFER)) {
    Location l=event.getBlock().getLocation();
    for (int i=0; i < 4; i++) {
      BlockFace face=BlockFace.values()[i];
      loc=new V10Location(new Location(l.getWorld(),l.getX() + face.getModX(),l.getY() + face.getModY(),l.getZ() + face.getModZ()));
      if (plugin.portalManager.insideBlocks.containsKey(loc)) {
        portal=plugin.portalManager.insideBlocks.get(loc);
        if (!portal.open)         continue;
        Portal destination=portal.getDestination();
        if (destination == null || destination.transmitter)         continue;
        for (        V10Location b : destination.inside)         b.getHandle().getBlock().setType(Material.AIR);
        portal.transmitter=false;
      }
    }
  }
}

Fixed version (ground truth):
@EventHandler() public void onBlockBreak(BlockBreakEvent event){
  Block block=event.getBlock();
  V10Location loc=new V10Location(block);
  Portal portal=plugin.portalManager.borderBlocks.get(loc);
  if (portal == null)   portal=plugin.portalManager.behindBlocks.get(loc);
  if (portal != null) {
    portal.delete();
    event.setCancelled(true);
    return;
  }
  portal=plugin.portalManager.insideBlocks.get(loc);
  if (portal != null) {
    if (portal.transmitter && block.getType() == Material.REDSTONE_TORCH_ON)     event.setCancelled(true);
    return;
  }
  Grill grill=plugin.grillManager.insideBlocks.get(loc);
  if (grill != null)   event.setCancelled(true);
  V10Location vb=new V10Location(block);
  Bridge bridge=plugin.funnelBridgeManager.bridgeBlocks.get(vb);
  if (bridge != null) {
    event.setCancelled(true);
    return;
  }
  bridge=plugin.funnelBridgeManager.bridgeMachineBlocks.get(vb);
  if (bridge != null) {
    if (plugin.hasPermission(event.getPlayer(),plugin.PERM_DELETE_BRIDGE))     bridge.delete();
 else     event.setCancelled(true);
    return;
  }
  plugin.funnelBridgeManager.updateBridge(loc);
  Region region=plugin.regionManager.getRegion(loc);
  if (plugin.blockUtil.compareBlockToString(block,region.getString(RegionSetting.GRILL_MATERIAL))) {
    grill=plugin.grillManager.borderBlocks.get(loc);
    if (grill != null) {
      if (plugin.hasPermission(event.getPlayer(),plugin.PERM_DELETE_GRILL))       grill.delete();
 else       event.setCancelled(true);
      return;
    }
  }
  Material type=block.getType();
  if (type == Material.REDSTONE_WIRE && region.getBoolean(RegionSetting.ENABLE_REDSTONE_TRANSFER)) {
    Location l=event.getBlock().getLocation();
    for (int i=0; i < 4; i++) {
      BlockFace face=BlockFace.values()[i];
      loc=new V10Location(new Location(l.getWorld(),l.getX() + face.getModX(),l.getY() + face.getModY(),l.getZ() + face.getModZ()));
      if (plugin.portalManager.insideBlocks.containsKey(loc)) {
        portal=plugin.portalManager.insideBlocks.get(loc);
        if (!portal.open)         continue;
        Portal destination=portal.getDestination();
        if (destination == null || destination.transmitter)         continue;
        for (        V10Location b : destination.inside)         b.getHandle().getBlock().setType(Material.AIR);
        portal.transmitter=false;
      }
    }
  }
}