[GS] TSL Mediterranean not working with GS

[Katsuraw]

I'm trying to start a TSL Mediterranean game, but it doesn't seem to want to load with the Gathering Storm expansion enabled. It puts me into the loading screen with the leaders and Sean Bean's voice comes on, I hear the loading sound early, but instead of clicking the start button, I get booted out and an error message appears, with Sean Bean's voice continuing in the background. I'm sure it's not a mod problem, because I have disabled everything to test what the issue was. It launched on the base game, it launched on Rise and Fall, but it failed to launch with Gathering Storm.