I'm not sure what's causing it, but it's not being eaten. Insects or slugs eat pieces of leaves. But the holes in your leaf are where the tissue has died and fallen out of the leaf.

Is the damage solely on the lighter portions?

Yes it is actually. I just happened to notice that! If that's the case, any idea what it is?

The discoloration pattern sort of makes me want to say it's a virus, but that's really just a guess. It could be something as simple as sun damage.

It's unlikely it's a virus. My first thought was foliar nematodes, but on second look, it looks more like either a cold damaged, sun damaged or water deprived area. I think whatever happened did so a while back. The tissue was damaged, turned light, then dark, then fell through.

Unless you see something to indicate it's spreading, I'd chalk it up to cold damage.

bk

I have never seen a hosta leaf turn anything but light or dark brown when it dies. Is it possible the purple is something accidentally sprayed or spilled?

Jon