[UNRESOLVED] [1.7.2] onItemRightClick called 4 times after using setTagCompound

Hi all, greetings from a newbie in MC modding 

I am writing a mod which adds repeating crossbow to MC. The plan is when user holds right mouse button it should shoot repeatly with a certain interval - until user releases the key.

As the first step I created a class which extends Item class, put it in tabCombat. I copied essential methods from ItemBow class to make it work same as a bow - till here everything works fine.

Then, I need a way to remember the status of a crossbow. i.e. it needs to know it is on fire. So I decided to use NBTTagCompound:

This is added at the beginning of onItemRightClick method. It's in Scala. What it does is if par1ItemStack doesn't have a tagCompound then create a new one for it. Then set "shooting" tag to true.

println("ON ITEM RIGHT CLICK")
Option(par1ItemStack.getTagCompound).getOrElse {
  par1ItemStack.setTagCompound(new NBTTagCompound)
}
par1ItemStack.getTagCompound.setBoolean("shooting", true)
....

And this is added at the beginning of onPlayerStoppedUsing. It just resets shooting tag.

println("ON PLAYER STOPPED USING")
par1ItemStack.getTagCompound.setBoolean("shooting", false)

Then something strange happened...

Before I added this tagCompound thing, while holding right mouse button on my item, both onItemRightClick and onPlayerStoppedUsing methods are called twice (one for client and one for server I guess?).

But after I added it, onItemRightClick is called 4 times while onPlayerStoppedUsing is still called twice. In the game UI I can also see that my item is used twice rather than once like before. And the first time happens very quickly - it's like I first click (press and release) the right mouse key then hold it again.

I don't understand why does this happen...

Thanks for reading and any help would be appreciated