Underminers spawn spam in nether mines of the Repurposed Structures mod.

[Vinzound]

As the title says, the Underminers spawn ridiculously commonly in the nether mineshafts in the Repurposed Structures mod, let's take into account that these mobs are rare to see in the overworld mines, and in YUNG's better mineshafts it is worse, but of course I'm not sure if that last one can be considered a bug.