When your camera clips under the terrain (easy to do, purposefully or accidentally), you can see this very clearly under the map.
Most developers put unwanted or hidden assets under the map. It’s not their fault that your camera can clip under terrain. They could fix it by putting a long part that covers the bottom underneath the map as well.
Never said it was their fault lol . And yep, they could definitely put a block. Slightly amusing to know that this is the treehouse. One could also make the whole thing transparent on each client or moving it to replicated storage or likewise.
if this wasn’t the demo place it would probably be a bit better hidden but since it IS the demo place its not a big deal