I changed out my wheels 12 months ago from steel wheels (with snow tires) back to stock alloy wheels with regular tires. Today, I attempted to change back to steel wheels with snow tires and noticed 2 opposing lug nuts on both front wheels were badly frozen on the studs. I've never, ever seen this before where I could hand loosen/tighten nuts 12 months ago, now required heavy torque on a breaker bar to get all the way off & all the way on.

I even managed to snap off a stud from the one rear hub.

What would cause this? I have a theory, but curious what people might think. I'm taking the van into a shop in a few days to have all studs & lug nuts replaced.