Riverbed Glitch?

Hello everyone. When I looked the Mangrove Shallows Cup I was fascinated by some maps of the tournament. I already downloaded some and I could play them without problems, with the exception of one, the one who most wanted to try, Riverbed. When I load the map, a Mongolia-like map appears, which is not what it should leave.

Does anyone know why this happens and how can I fix it, or if I am doomed to not be able to play it?

I'm playing steam by the way, however, I had no problem playing other maps of the MSC like Bog Islands or Bog Forest.