Yet another thing I don't know that you can do anything about. Back in the day we had Magnum Torches that prevented mob spawning in a 64x64 area, but they didn't interfere with cursed land, spawners, soul vials, etc. The mob totems (in a creeper, ocelot, ocelot totem) seem to interfere with everything. I couldn't place a mob in a soul vial, and ever better worse, the Gaia Guardian can't spawn mobs at halftime.

Now, while I am going to take shameless and heinous advantage of this while it lasts, it does feel pretty cheaty and is probably not what you want in a challenging pack like this. Pic is included below.

(Two Battles Later)
One really funny side-effect of this is that it seems the Mob Totems gets confused when the mob that's spawning is a baby zombie riding a chicken due to the chicken not being a hostile mob, so it will spawn the chicken with an invisible baby zombie on it. When you kill the chicken, the zombie de-spawns. I'm going to assume that this won't happen with spider-riding skeletons because those are both hostile mobs.

Expected Behavior

Gaia Guardian (I and II) spawn mobs when they get to that point in the fight.

Current Behavior

Blissful silence and time to reload. Specifically, the Gaia Guardian floats up, hangs for a while like Jordan, then continues the fight.

Possible Solution

No idea. I'm not a mod-pack developer. Perhaps the Mob Totems config?

Steps to Reproduce

Put a mob totem (creeper flavor) next to your Botania Guardian fighting area, fire up the totem and start the fight.

Without Mob Totems, you can put some IF mob crushers with range addons under the arena or other mob killing area stuff, and have same fight without mobs interrupting you.