Two things regarding Curgen's Volcano:
1. The AI is unable to cast it (Similar to how it was unable to cast Arcane Monolith, so maybe extend Arcane Monolith fix to Curgen's Volcano?)
2. Various issues with surviving units / terrain on the Volcano, see images.
Image #1: Surviving Units. Will remain in game even after Empire of Yithril has been eliminated.
Image #2: River remained on the Volcano.
LH Mods by Primal