I'd been blaming the kids for repeatedly messing up the cushions on the love seat, despite their protestations of innocence. As soon as I put the cushions back in place they'd be in disarray all over again. It didn't make sense. It was just happening too often. Even my kids aren't usually that sloppy.
Finally, I've figured out. Taffy likes to sunbathe in the light coming through the living room windows. However, with the cushions in their rightful places she can't find a comfortable place to bask in the sun. So, she knocks them over to make a bed for herself.
Rather resourceful of her, actually. A pain in the butt, but resourceful.