After the update 1.17.30 several bugs occurred in my existing world, these errors only occur in my base, i.e. in the chunks that were loaded directly after the update:

1. All axolottls and tropical fish are despawned
2. Cows that were in the water (farm) are despawned
3. Tamed animals, cats and dogs no longer sit down or accept food. These can no longer be clicked on.
4. Villager max levels have changed their occupations and have partly lost levels