Huge Chunks of World disappearing!

Twice in the past few days there has been complete destructions of huge parts of the world on my friend's realm. This is a pure survival server and I fell into the void then respawned and fell into the void where I respawned on the first world that got destroyed. He started a new world and the same thing happened with everything disappearing including the bedrock. Something about the new update must have something to do with this but I hope it gets fixed or there is no point playing if everything is going to get deleted anyway.