The issue is the map is not completely loaded in or rendered in. The 'holes' are what the map looks like under the mesh. Towards the end of the video you can see where the 'holes' were - have now filled in with water. The Crystal Isles map is about the same size as the Genesis Map which requires additional memory when hosting a live server on line. That would also require additional load time on single player.
been there. done that. got the t-shirt.