That's interesting! Well, I can say that since I've been here it's been overwhelmingly been US MDs that are in the IM program
It's probably because it is a big academic program in California, so it's gotten more competitive and now draws a lot more US MDs that want to match in California compared to before. I also just looked up how much USC had to SOAP to fill their incoming class and they haven't had to since at least 2013 (don't have info on anything earlier than that).
Regardless, I hope they didn't dissuade you too much from matriculating, and that I might see you around on campus this coming school year