Can someone explain this to me? I have two scrap pieces, both of which I thought were veg tanned leather. I was trying to make toys for my dog out of them, and the one on the right doesn't seem to cook.

For context, I purchased both pieces from Tandy Leather. I've been an amateur costume leather worker for many years. I mostly just make masks and other moldable items. I've never come across something like this. Also if you look closely, does the one on the right look odd as if it's not genuine leather? There's a weird pattern in it. Could it be some type of genuine leather that just happens to not be moldable? Because it smells like leather. There's no mistaking that smell. I'm genuinely so confused.