1.6.2 addPotionEffect not working

For some reason, I cannot get addPotionEffect to work correctly.

The method that I had working in 1.5.2:

[/code

    public boolean onLeftClickEntity(ItemStack stack, EntityPlayer player,

            Entity entity) {

        if (entity instanceof EntityLiving) {

            EntityLiving entityLiving = (EntityLiving) entity;

            entityLiving.addPotionEffect(potionEffect);

        }

        return false;

    }

And this is the code for the item.
[code]
        thoriumSword = new ItemPotionSword(ItemIds.THORIUM_SWORD_ID, TOOL_THORIUM, Strings.THORIUM_SWORD_NAME, new PotionEffect(Potion.wither.id, 1000, 1, true), Strings.TEXTURE_FOLDER + ":" + Strings.THORIUM_SWORD_NAME);

Note:

I stepped through it and nothing went wrong, it just didn't work for some reason.  Also, it will occasionally work, but other times it won't work.

Source:

https://github.com/Shalashalska/Melior-Metallum/blob/master/metallum_common/metallum/item/ItemPotionSword.java

Edit: Now it started working properly again.