I updated my world to the most recent snapshot. After building a new structure on the world, I tried to update the map I had of the spawn area. This caused the map to corrupt as shown in the attached image. I tried creating a new map and re-doing it, but it still appears to have the same issues. I thought that it was possible there was an issue since I was underground when the map was drawn, and tried again above ground. This resulted in the same issue. I have also attached a image (in spectator mode) of the area above the location in the map showing there were no structures built above the map.