Aquifer borders generate floating

Can confirm on seed -9235201 and location -3931 12 328

Can also confirm this in 21w44a. This ticket relates to MC-236896. Here are some extra details regarding this problem.

The Bug:

Broken aquifer walls/borders commonly generate underwater.

As a result of this issue occurring, blocks can be seen floating underwater in bizarre and unnatural ways.

Steps to Reproduce:

• Create a world with the following seed and teleport to the following coordinates.

Version: 21w44a
Seed: 8731922480704591603
Coordinates: /execute in minecraft:overworld run tp @s -2063.53 17.64 -1105.30 -2370.76 43.97

• Take note as to whether or not broken aquifer walls/borders commonly generate underwater.

Observed Behavior:

Broken aquifer walls/borders commonly generate underwater.

Expected Behavior:

Broken aquifer walls/borders would not generate underwater.