If I previously had the Caves and Cliffs option activated, when updating my world and activating the wild at first nothing happened, the new chunks were generated correctly but a few minutes later when I wanted to mine near my base I noticed that the negative layers were bedrock and I wanted to check in creative, so I created a copy of my world and when I started breaking the bedrock in creative all the old chunks had been generated from bedrock
If I previously had the Caves and Cliffs option activated, when updating my world and activating the wild at first nothing happened, the new chunks were generated correctly but a few minutes later when I wanted to mine near my base I noticed that the negative layers were bedrock and I wanted to check in creative, so I created a copy of my world and when I started breaking the bedrock in creative all the old chunks had been generated from bedrock