You're right, something weird happened when I pasted the link in to submit it. Maybe a bug in Chrome on Android, because I just tested it again and found it only copied the link to the blog and not the specific post.
If Dang or any other mods see this, please correct the link.
I think it's their own site. When I shared the link from my phone to my computer the same thing happened — the link got changed to the main blog page. As someone else mentioned I think it's the <link rel="canonical"> in the header.
If Dang or any other mods see this, please correct the link.