The graphic does explode, however it is difficult to test without being able to get cold. :X
From the sound it does appear to hit targets twice, but, not 100% sure.
So far, all I know is.
I have to
-equip highlords amulet
-equip darksight helm(not required though some other helms seem to work in its place like arreats face, but you have to have a helm)
-equip flying knife
-flying axe needs to be in left hand
-balanced axe needs to be in right hand
-war javelins work
-tried some of the different kinds of throwing some work, some dont
-pick up and reequip the dagger to activate.
When messing with the different javelins I noticed that sometimes the javelin will always fire first. It seems like the the weapons are actually swapping when you, when you pick up and reequip your your knife.
Here is another pic. I am using double throw and they both could out as knives, when I normal throw with the javelin in mainhand, it comes out a javelin.
So, that is basically what the bug is. And, I don't know if I am actually duping my knife to be in both hands. I can test that tomorrow with amp on proc.
As you can see here, naturally the knife is in my main hand, when I reequip it, then it seems to swap hands. Look at where the thrower is holding the knife in his hand.