Low IV + tough to catch?

I've been coming across pokemons that are way too hard to catch given their CP (ex: 300cp Eevees breaking out 10+ times), then when I finally got them, they turn out to have super low <50 IV... Is this happening to anyone else?

I'd suggest that catch difficulty should correspond to not only CP, but IV also. If you make us devote huge efforts to catching one pokemon, it shouldn't be a terrible one.