It's not a new pattern though.

Before they've done it for telemetry and identifying which initiative this click is from. Nowadays it's just that they're redirecting the default route to a particular site after, so they could potentially switch the site they redirect to later.

While a small annoyance to mobile users which go there from sites like hn, it does give the owner of the site a tiny amount of control where ppl end up on their site.

At least that's my interpretation...