Even prions undergo evolution and they are just molecules bumping around into stuff. They clearly don't have feelings about whether or not they propagate, they just do.
Are you sure they undergo evolution, and aren't just a self-spreading phenomenon like Fire?
They are a self-spreading phenomenon like fire in the sense that they aren't alive. But what's different about them is they can develop varying characteristics that pass onto their progeny. The characteristics that are more successful at propagation result in more prions of that type existing, which over time results in the prion's evolution. It's well-documented in the literature, but it is interesting to observe that evolution can occur without DNA or RNA. That said, their evolution is probably slower and more confined than things using DNA and RNA because there is only so much variability a particular protein can have.
I was unaware of the literature on different misfolds able to replicate their own specific misfolds.