In the editor preview, I restarted and there was blue all around me. I didn't fall through, but there weren't any textures. I exited the editor and was brought to the main menu. But, instead of showing the circling view of Stratis, there was a crumbled mess of terrain textures that looked like the map was pulled by a string through a bottleneck. I exited the game, then opened it back up and it was fine.