This bug exists up to version 1.20.40.20, and is still not fixed.

I will give 2 examples, one bug:

1 video: We need to go into creative mode, turn on flight mode, and click on sneak.
How it worked before: You could fly, and at the same time use the sneak mode.
Now: You're in flight mode, not like you can't start sneaking (because of this, the mechanics of the game break down, for many players. For example, in construction, you will not be able to put a block to the hatch, because then you will open / close the hatch, instead of putting a block next to it).

2 video: You need to go into the water in any mode, and you can't help but start sneaking. And this also breaks the mechanics of the game!
Previously, you could swim in the water (example: you will not be beaten by a magma block).
Sechas: Whatever you do, you will not be able to start sneaking in the water (and you will be beaten by magma).