How do I make a projectile drop but not duplicate?

I wanted to make a mod where you can throw and item, and it doesn't vanish when it hits a mob. I made it so if it hits a mob, the item will drop itself. This works for the most part, but I'm having a bug where if I throw the item into the air and it hits the player it keeps duplicating. I've tried making the item despawn when it hits a player, but this makes the item stop working until I reload. 

Is there a way to make the procedure only run if the projectile doesn't hit a player? Or maybe only run if it does damage? I'm really new to mcreator so I'm just sure where to look.