The Bug:

The bottom parts of aquifers aren't always surrounded by blocks which can occasionally cause them to spill into caves in ways that appear bizarre.

Steps to Reproduce:

• Enter the following seed and coordinates.

• World Type: Single Biome, Lush Caves
  Seed: 8009750494097954235
  Coordinates: /execute in minecraft:overworld run tp @s -2720.30 -20.00 9201.30 -314.61 5.98

Observed Behavior:

The bottom parts of aquifers aren't always surrounded by blocks which can occasionally cause them to spill into caves in ways that appear bizarre.

Expected Behavior:

The bottom parts of aquifers would always be surrounded by blocks so that they wouldn't spill into caves in ways that appear bizarre.