Ghast fireballs move incorrectly when hit with knockback enchantment

To reproduce, use one weapon enchanted with knockback and another weapon not enchanted with knockback to knock back a ghast fireball. The weapon without knockback will repel the projectile properly, but the weapon with knockback will make the projectile travel too quickly horizontally and slower in height. This can be annoying when trying to kill ghasts using a knockback sword.