Thanks, I'll try that.
Yeah, I deleted almost all of the potentially relevant server files and that didn't work, so maybe its client side at this point, like your post seems to suggest.
I used the fog of war cheat to confirm a map reset included all the biomes, but now I can't turn it off. I've tried deleting saves, deleting character profiles, removing admin from my steam ID, and rolling back the server to the earliest backup, to no avail. Does anyone know how to disable the fog of war for my character?