Please help the ground is gone

 As you can see in the images below, the textures for the ground/earth just simply don’t exist and have been replaced with… beige checkerboard? I don’t know what on earth is causing this, or if there’s a file that’s corrupted, or what.
 I am playing Fjordur on a MacBook pro, i know already not the greatest situation, but EVERYTHING else about the game is working perfectly. Everything is fine, all other textures and sounds and movement, etc. just this ONE thing, but it bothers me so much that i can’t really just ignore it and keep playing. What i’ve done to explore the issue:

• Restart the game multiple times • Restart the laptop multiple times • Alter game resolution/texture settings a lot • Took off any mods I had active in case one was corrupted • Verified game files (playing on steam, verified through steam) • Try a different map - Now THIS one is interesting. I started new games on The Island, Lost Island, Crystal Isles, Ragnarok, and Valguero. The first 2 were the same thing as Fjordur but then Crystal Isles, Valguero AND Ragnarok were perfectly fine?! the ground textures were all loaded in as they should be and everything was perfect. I went back to try Fjordur and the Checkerboard is still there… It’s great that not ALL the maps are having this issue but i really want to play Fjordur or Lost Island since they are relatively new DLCs right? but they’re the ones that are broken. So what is wrong with those 3 maps?! (The Island is included) what happened to the ground texture and what can i do to fix it? Please help me!!