Steps to reproduce:

1. Make a behavior pack
2. Make a custom item
   1. That is "throwable"
   2. That has "projectile_entity" of Minecraft:fireball
3. Load minecraft
4. Make a world with Experimental Gameplay on
5. Use the item

Expected Results: Projectile will fly until it hits a block or entity.

What Actually Happened: Projectile explodes/hits something about 3-4 blocks away from the player.

In my testing, this happens to fireball, small_fireball, and dragon_fireball. It may happen to others.

In my testing, this does not happen to arrow, egg, snowball, enderpearl, trident. It may not happen to others.

I only edited the item in the behavior pack, I did not edit the entity files.