[Bug?] Mobs have negative level

[GeaRetteX]

Hi, i run a server with my friends, i tweaked the values of stats gained per level for the mobs (on the config file), but now every overworld mob has negative level, and half a heart of max hp, this doesn't happen neither on the Nether or the End, or any modded dimension, it's just on the Overworld

We play the Medieval Minecraft MMC4 server pack, if that helps