Minecraft huge deep holes

I play on a Xbox One X and my Minecraft survival world I have been playing for about 2 months and a hour a day. And then all of a sudden, these huge deep holes appear and i have no idea why. There is a similar question about the issue and I have tried all the things people said would work. I have gone to the nether, logged out and logged back in, saved and quit and also made a copy of the world. With the hole I can jump down and I fall into the void bellow killing myself in a matter of seconds. I would really appreciate it if someone could help because I have made a lot of advancements and also have been incredibly lucky with this.

This is not my world but this is what happened and there are many of them where my house and everything else resigns.