Identify Fisheye Contamination

So, I've got a piece of furniture right here or a mirror. And we ran into some real problems with fisheye on there. If you haven't heard of the term fisheye, that's um what a result of what happens if you got a contaminant on a piece of furniture or cabinets or some type of wood painted surface. When you spray paint on it or a primer, it'll fisheye