Zombies have a 100% chance to spread fire when attacking while on fire

Recently it was updated to where when Zombies attack an entity while burning in daylight, they will spread the fire to that entity. This seems to have been messed up however, as there is a 100% chance to spread fire to the entity when attacking instead of it being a rare chance, making them more dangerous.

Step to Reproduce:
1. Spawn a Zombie
2. Make sure they are in daylight or on fire
3. Let them attack you while they are on fire

Expected Result:
They spread the fire to the entity they are attacking every once in a while

Observed Result:
They spread the fire to the entity they are attacking every hit