This post you are commenting on (*6316) is a link post that points to the other one (*4663)

The normal behavior for link posts in HN is that the title takes you to the link address, not to the post address.

To enter the post address, you need to hit the "discuss"/"x comments" button.

So, what you describe is HN working as expected AFAICT, it's just a bit counterintuitive because it's an HN post linking to another, which is uncommon

Here is a self referencing HN post: https://news.ycombinator.com/item?id=33130986