Save Game loads new random overworld upon entering caves

Whenever I enter the caves in my save, it immediately creates a new overworld instead of taking me to my already existing caves. I've rolled back server as far as it can go and still have this issue. I've verified my game files on steam, and also disabled all mods I was using. I had no mods that affected world generation ever loaded on this server. Loading into different caves loads different maps, but the same map loads each time instead of loading the caves. I can return to my original file by going back through the caves, but I don't seem to be able to ever enter the caves in the game's current state.