I mean it's probably safe to assume it will be a D1 marketed route and somebody maybe just jumped the gun with website updates. They are still selling FC fare filings for the D1 cabin (second to last letter of fare basis code is an F), but that doesn't mean they will kick you out once they get around to putting D1 fare filings on route if you purchase an FC fare or applied an RUC on route (as previous poster noted).

There are actually existing D1 fare filings on route, but not for the non-stop flight. All the existing D1 fare filings require SLC connections in the routing rules.