Recently reddit has also started making its official app generate links to posts via the domain "reddit.app.link", instead of normal reddit.com urls. These new links automatically send everyone on mobile to the app store to download the official app, even if they clicked from inside a third-party app.

As far as I can tell, the only way to make the links work on mobile is to install the official app (once you do, they'll open the linked post inside it).