—After having the mirrors replaced, she noticed the mirrors on the car parked next to hers were also melting.—
I infer from this that the fact that her car is a Priuth is irrelevant. Rather, it is an issue with too much reflected solar energy coupled with the direct sunlight that is death to plastic car parts, regardless of the make or model.
But mentioning it is a Prius in the headline is a good hook. Grabs the readers.
Heck, if I was a headline writer, I might just make that "fact" up, because it makes for a more attractive story.