Last beta there were holes in the world which wouldn't appear until you got close to them, but if you moved away again they would disappear. This has sort of been fixed, certain chunks still won't appear until I get close, and once I do it takes significantly longer to render these specific chunks and am unable to move over them. However, once they finally render, even if I move away they stay visible which is great! The game prioritized rendering a mountain in the distance before the chunk right in front of me and it took a couple of minutes until it finally appeared. World seed is 286844226