[1.12.2] Resistance effect never ends

Title. I have an enchantment that gives player 30 seconds of resistance for the cost of 30 durability, which is activated when sneaking + right click the item.

The ability works fine, except that the effect never ends and stays at 0 seconds permanently. The only way to fix it is closing the world and entering again.

Additional note: the sound effect also doesn't seem to work

@SubscribeEvent
	public static void sneakBoost(InputUpdateEvent event){
		if (event.getMovementInput().sneak){
			EntityPlayer player = event.getEntityPlayer();
			if (player.getActiveItemStack().getItem().isShield(player.getActiveItemStack(), player)){
				if (!player.isPotionActive(MobEffects.RESISTANCE)){
					player.getHeldItemOffhand().damageItem(30, player);
					player.addPotionEffect(new PotionEffect(MobEffects.RESISTANCE, 600, 0));
					player.world.playSound(null, player.posX, player.posY, player.posZ, SoundEvents.BLOCK_SHULKER_BOX_CLOSE, SoundCategory.NEUTRAL, 2.0F, 1.0F);
				}
			}
		}
	}