I have no idea why it has the root URL. I pasted the direct URL but it looks like HN didn't like it. I can't modify the URL unfortunately. If a moderator could update it that would be great.
You can fix your website: the post has a <link rel="canonical" href="https://www.blockloop.io/" /> in it, which tells the HN software that the main URL for your post is your homepage.
Thank you. I deleted that tag for now until I figure out how to set it properly with Jekyll. I'll admit that SEO is not something that I've worked with extensively.
The submitted URL was correct but, as detaro points out, the canonical URL wasn't, and our software now uses canonical URLs when it finds one.