[Parity] Aquifers often generate with harsh straight borders

When generating a new Caves & Cliffs experimental world, you often find that the aquifers have straight borders on the outside. This was fixed in the Java 1.18 snapshot, so this is considered a parity bug. (MC-237109)

The seed is 1034258908, 1787306075, and -1217777468. Coordinates are in the screenshot.

Expected Result
The aquifers generate with smoother, more natural borders.