Program: 187711
Project: 187711
Buggy source:
public void Timer(){
  if (Status != WolfState.Despawned) {
    if (Timer != -1) {
      StopTimer();
    }
    Timer=MyWolf.Plugin.getServer().getScheduler().scheduleSyncRepeatingTask(MyWolf.Plugin,new Runnable(){
      public void run(){
        if (Status == WolfState.Despawned || getOwner() == null) {
          StopTimer();
        }
 else {
          if (Status == WolfState.Here) {
            EntityWolf wolf=((CraftWolf)Wolf).getHandle();
            Block CheckWayPoint=MyWolfUtil.getServer().getWorld(getLocation().getWorld().getUID()).getBlockAt(wolf.pathEntity.c().a,wolf.pathEntity.c().b,wolf.pathEntity.c().c);
            MyWolfUtil.Log.info("String_Node_Str");
            MyWolfUtil.Log.info("String_Node_Str" + CheckWayPoint);
            MyWolfUtil.Log.info("String_Node_Str" + wolf.pathEntity.c().a);
            MyWolfUtil.Log.info("String_Node_Str" + wolf.pathEntity.c().b);
            MyWolfUtil.Log.info("String_Node_Str" + wolf.pathEntity.c().c);
            SitTimer--;
            if (SitTimer <= 0) {
              Wolf.setSitting(true);
            }
            if (isPickup) {
              for (              Entity e : Wolf.getNearbyEntities(MyWolfConfig.PickupRange,MyWolfConfig.PickupRange,MyWolfConfig.PickupRange)) {
                if (e instanceof Item) {
                  Item item=(Item)e;
                  int amountleft=Inventory[0].addItem(item);
                  if (amountleft == 0) {
                    e.remove();
                  }
 else {
                    if (item.getItemStack().getAmount() > amountleft) {
                      item.getItemStack().setAmount(amountleft);
                    }
                    if (MyWolfUtil.hasSkill(Abilities,"String_Node_Str")) {
                      amountleft=Inventory[1].addItem(item);
                      if (amountleft == 0) {
                        e.remove();
                      }
 else {
                        if (item.getItemStack().getAmount() > amountleft) {
                          item.getItemStack().setAmount(amountleft);
                        }
                      }
                    }
                  }
                }
              }
            }
            if (Behavior == BehaviorState.Agressive) {
              if (Wolf.getTarget() == null) {
                for (                Entity e : Wolf.getNearbyEntities(10,10,10)) {
                  if (MyWolfUtil.getCreatureType(e) != null) {
                    Wolf.setTarget((LivingEntity)e);
                  }
                }
              }
            }
          }
          if (Status == WolfState.Dead) {
            RespawnTime--;
            if (RespawnTime <= 0) {
              RespawnWolf();
            }
          }
        }
      }
    }
,0L,20L);
  }
}

Fixed version (ground truth):
public void Timer(){
  if (Status != WolfState.Despawned) {
    if (Timer != -1) {
      StopTimer();
    }
    Timer=MyWolf.Plugin.getServer().getScheduler().scheduleSyncRepeatingTask(MyWolf.Plugin,new Runnable(){
      public void run(){
        if (Status == WolfState.Despawned || getOwner() == null) {
          StopTimer();
        }
 else {
          if (Status == WolfState.Here) {
            SitTimer--;
            if (SitTimer <= 0) {
              Wolf.setSitting(true);
            }
            if (isPickup) {
              for (              Entity e : Wolf.getNearbyEntities(MyWolfConfig.PickupRange,MyWolfConfig.PickupRange,MyWolfConfig.PickupRange)) {
                if (e instanceof Item) {
                  Item item=(Item)e;
                  int amountleft=Inventory[0].addItem(item);
                  if (amountleft == 0) {
                    e.remove();
                  }
 else {
                    if (item.getItemStack().getAmount() > amountleft) {
                      item.getItemStack().setAmount(amountleft);
                    }
                    if (MyWolfUtil.hasSkill(Abilities,"String_Node_Str")) {
                      amountleft=Inventory[1].addItem(item);
                      if (amountleft == 0) {
                        e.remove();
                      }
 else {
                        if (item.getItemStack().getAmount() > amountleft) {
                          item.getItemStack().setAmount(amountleft);
                        }
                      }
                    }
                  }
                }
              }
            }
            if (Behavior == BehaviorState.Agressive) {
              if (Wolf.getTarget() == null) {
                for (                Entity e : Wolf.getNearbyEntities(10,10,10)) {
                  if (MyWolfUtil.getCreatureType(e) != null) {
                    Wolf.setTarget((LivingEntity)e);
                  }
                }
              }
            }
          }
          if (Status == WolfState.Dead) {
            RespawnTime--;
            if (RespawnTime <= 0) {
              RespawnWolf();
            }
          }
        }
      }
    }
,0L,20L);
  }
}