A clear-cut example is butternut squash which has like 212% of your RDA of vitamin A, and 35% of vitamin C, whereas spaghetti squash barely hits 5% vitamin C, and has clost to zero vitamin A (in 100g).
Why do some retain vitamins so much better?
It’s not that certain plants retain vitamins better than other plants, it’s just that they contain different chemical compounds to start with. There are many different carotenoids that plants can possibly have, however only a small subset of carotenoids (e.g. α-carotene, β-carotene, and β-cryptoxanthin, etc) actually have vitamin A activity.