Soul campfires are supposed to deal twice the damage than a normal campfire. However, this does not apply to Evokers. Evokers take the same damage from soul campfires as if they are standing on a normal campfire, instead of taking 2 damage per hit, they only take 1.

Steps to Reproduce:
1. Place a soul campfire.
2. Spawn an Evoker on the soul campfire and make sure it doesn't escape.
3. Count the hits it is taking. (24 hits to be exact and supposed to be only 12 hits)
4. Try doing it with a normal campfire for comparison.

I was just playing around with mobs and campfires then I stumbled upon this bug.