Is it by design that a loading.js file in a dynamic route is never prefetched? The docs promise Instant Loading States (https://nextjs.org/docs/app/building-your-application/routing/loading-ui-and-streaming#instant-loading-states), but that just doesn't seem to work in a dynamic route. It does work if I put the file at /post/loading.js instead in my example, but I don't know if that is intended.

All of the above applies to layout.js files as well (and possibly more), they do not get prefetched when placed behind a dynamic route segment.

(Note: I do run it in production mode, I know Links aren't prefetched in development mode)