Wait, actually I have had all three version of Fallout 2 (and it's predecessor). First I bought the games on cd and installed them in Program Files. Then several years later I got the Steam Versions. But then later when I got a larger monitor and the steam versions stopped running, I bought the Gog versions. It is the Gog versions I have installed at the moment. However, it turns out that on all three versions of Fallout 2, I had these exact same problems I discussed above and I have no idea how to prevent them from happening.
I would much appreciate it if someone could tell me how to stop them because the random caves you encounter seem like great places to get experience!