Horse not Spawning during "In the Saddle"

Im playing the Playstation 4 version and Im having serious problems with the mission "In the Saddle" in the Hinterlands. I did the first race just fine. Im trying to do the second one but the horse wont spawn. Sellena keeps telling me its still set up, but there is no horse to ride. Ive exited out of the Hinterlands, and gone back in and nothing happened. Ive tried doing a few other missions in the hinterlands, and have come back and still a horse wont spawn. Ive even logged out, closed the app, and restarted the PS4, and it still wont spawn. What else can i do to get the horse to spawn so i can complete the mission??