At some point in a listing, e.g. https://opensource.posit.co/blog/ thumbnails lose the rounded corner effect. E.g. notice here the "purrr" posted has square corners, as does every post that comes afterwards: <img width="1287" height="803" alt="Image" src="https://github.com/user-attachments/assets/dfc87013-04e9-4f99-a956-cb442ce62e44" />
At some point in a listing, e.g. https://opensource.posit.co/blog/ thumbnails lose the rounded corner effect.
E.g. notice here the "purrr" posted has square corners, as does every post that comes afterwards: