Floatings aquifers and blocks inside a cave. (potential duplicate, see MC-237155)

I've created a world (seed: 5262791106752089645), and in a cave near spawn (X -234; Y 87; Z 56) there are a few aquifers and a few blocks flying, probably it's a small bug with the terrain generation and it's not game breaking, but anyways.

Here is a small video and a few screenshots:

https://youtu.be/TzhxrITQsNk