Planet that should have been swallowed by its star somehow still orbits

Why is a planet orbiting a star that should have gone through a giant phase?

https://arstechnica.com/science/2023/06/planet-that-should-have-been-swallowed-by-its-star-somehow-still-orbits/?utm_brand=arstechnica&utm_social-type=owned&utm_source=mastodon&utm_medium=social