I think authors are just realizing there's no real reason to feel limited to a narrow set of genre rules in their writing. There's no reason a mystery novel can't have fantastic elements in it. Similarly, there's no reason why your epic fantasy series can't have elements of a mystery.
Patrick RothfussTo be both rich and handsome was bad enough. But to have a voice like honey over warm bread on top of that was simply inexcusable.
Patrick Rothfuss