1. I created a new world.(seed: 7242249954336383171)
2. I was give a command block.
3. Iwrited there /clone 1 2 3 4 5 6 7 8 9 masked and that says that can't access to blocks in outside of the world.
4. I teleport me at 1 2 4.
5. I falled to void.
6. I don't pressed F3 but game crashed.