Summary:

Lily pad can be generated in caves under the swamp biome. In java, lily pads are not generated in caves, and I also think lily pad generation in caves is illogical.

Seed: 63654350
Coords: 386 15 -1956
Coords: -5769 17 -14377
Coords: -5770 48 -14435

Steps to reproduce:

1. Create a world with the specified seed.
2. Teleport to the specified coordinates.
3. See how the lily pad was generated in the caves.

Observed results:

Large caverns with aquifers below the swamp biome generate a lily pad.

Expected results:

For parity with java and for logical generation of the world, there should not be a lily pad in the caves.

Image: