Program: 24509
Project: 24509
Buggy source:
@Override public void onPlayerInteract(PlayerInteractEvent event){
  player=event.getPlayer();
  if (event.getAction().equals(Action.RIGHT_CLICK_BLOCK)) {
    if (event.getClickedBlock().getType() != Material.CHEST && event.getClickedBlock().getType() != Material.IRON_DOOR_BLOCK && event.getClickedBlock().getType() != Material.WOODEN_DOOR && event.getClickedBlock().getType() != Material.STONE_BUTTON && event.getClickedBlock().getType() != Material.LEVER && event.getClickedBlock().getType() != Material.MINECART && event.getClickedBlock().getType() != Material.STORAGE_MINECART && event.getClickedBlock().getType() != Material.POWERED_MINECART && event.getClickedBlock().getType() != Material.DISPENSER && event.getClickedBlock().getType() != Material.BOAT && event.getClickedBlock().getType() != Material.BURNING_FURNACE && event.getClickedBlock().getType() != Material.FURNACE && event.getClickedBlock().getType() != Material.CAKE_BLOCK && event.getClickedBlock().getType() != Material.NOTE_BLOCK && event.getClickedBlock().getType() != Material.WORKBENCH && event.getClickedBlock().getType() != Material.TNT) {
      if (player.getItemInHand().getType() == Material.SUGAR) {
        int numOfSugar=player.getItemInHand().getAmount();
        if (player.getHealth() < 20) {
          if (numOfSugar == 1) {
            player.setItemInHand(null);
          }
 else {
            player.getItemInHand().setAmount(numOfSugar - 1);
          }
          if (props.od.equals(true)) {
            if (scheduleHandler.isOD == 1) {
              double dmg=props.odDamage * 2;
              int newDmg=(int)dmg;
              player.damage(newDmg);
            }
 else {
              scheduleHandler.isOD=1;
              scheduleHandler.schedule("String_Node_Str",player);
            }
          }
          if (props.healing.equals(true)) {
            double heal=props.healAmnt * 2;
            int newHealth=event.getPlayer().getHealth() + (int)heal;
            player.setHealth(newHealth);
          }
        }
        scheduleHandler.schedule("String_Node_Str",player);
      }
    }
  }
 else   if (event.getAction().equals(Action.RIGHT_CLICK_AIR)) {
    if (player.getItemInHand().getType() == Material.SUGAR) {
      int numOfSugar=player.getItemInHand().getAmount();
      if (player.getHealth() < 20) {
        if (numOfSugar == 1) {
          player.setItemInHand(null);
        }
 else {
          player.getItemInHand().setAmount(numOfSugar - 1);
        }
        if (props.od.equals(true)) {
          if (scheduleHandler.isOD == 1) {
            double dmg=props.odDamage * 2;
            int newDmg=(int)dmg;
            player.damage(newDmg);
          }
 else {
            scheduleHandler.isOD=1;
            scheduleHandler.schedule("String_Node_Str",player);
          }
        }
        if (props.healing.equals(true)) {
          double heal=props.healAmnt * 2;
          int newHealth=event.getPlayer().getHealth() + (int)heal;
          player.setHealth(newHealth);
        }
      }
      scheduleHandler.schedule("String_Node_Str",player);
    }
  }
  player.updateInventory();
}

Fixed version (ground truth):
@Override public void onPlayerInteract(PlayerInteractEvent event){
  player=event.getPlayer();
  if (event.getAction().equals(Action.RIGHT_CLICK_BLOCK)) {
    if (event.getClickedBlock().getType() != Material.CHEST && event.getClickedBlock().getType() != Material.IRON_DOOR_BLOCK && event.getClickedBlock().getType() != Material.WOODEN_DOOR && event.getClickedBlock().getType() != Material.STONE_BUTTON && event.getClickedBlock().getType() != Material.LEVER && event.getClickedBlock().getType() != Material.MINECART && event.getClickedBlock().getType() != Material.STORAGE_MINECART && event.getClickedBlock().getType() != Material.POWERED_MINECART && event.getClickedBlock().getType() != Material.DISPENSER && event.getClickedBlock().getType() != Material.BOAT && event.getClickedBlock().getType() != Material.BURNING_FURNACE && event.getClickedBlock().getType() != Material.FURNACE && event.getClickedBlock().getType() != Material.CAKE_BLOCK && event.getClickedBlock().getType() != Material.NOTE_BLOCK && event.getClickedBlock().getType() != Material.WORKBENCH && event.getClickedBlock().getType() != Material.TNT) {
      if (player.getItemInHand().getType() == Material.SUGAR) {
        int numOfSugar=player.getItemInHand().getAmount();
        if (player.getHealth() < 20) {
          if (numOfSugar == 1) {
            player.setItemInHand(null);
          }
 else {
            player.getItemInHand().setAmount(numOfSugar - 1);
          }
          if (props.od.equals(true)) {
            if (scheduleHandler.isOD == 1) {
              double dmg=props.odDamage * 2;
              int newDmg=(int)dmg;
              player.damage(newDmg);
            }
 else {
              scheduleHandler.isOD=1;
              scheduleHandler.schedule("String_Node_Str",player);
            }
          }
          if (props.healing.equals(true)) {
            double heal=props.healAmnt * 2;
            int newHealth=event.getPlayer().getHealth() + (int)heal;
            player.setHealth(newHealth);
          }
          scheduleHandler.schedule("String_Node_Str",player);
        }
      }
    }
  }
 else   if (event.getAction().equals(Action.RIGHT_CLICK_AIR)) {
    if (player.getItemInHand().getType() == Material.SUGAR) {
      int numOfSugar=player.getItemInHand().getAmount();
      if (player.getHealth() < 20) {
        if (numOfSugar == 1) {
          player.setItemInHand(null);
        }
 else {
          player.getItemInHand().setAmount(numOfSugar - 1);
        }
        if (props.od.equals(true)) {
          if (scheduleHandler.isOD == 1) {
            double dmg=props.odDamage * 2;
            int newDmg=(int)dmg;
            player.damage(newDmg);
          }
 else {
            scheduleHandler.isOD=1;
            scheduleHandler.schedule("String_Node_Str",player);
          }
        }
        if (props.healing.equals(true)) {
          double heal=props.healAmnt * 2;
          int newHealth=event.getPlayer().getHealth() + (int)heal;
          player.setHealth(newHealth);
        }
        scheduleHandler.schedule("String_Node_Str",player);
      }
    }
  }
  player.updateInventory();
}