The Bug:

Magma blocks can generate inside of icebergs.

Here is an example:

Seed: 4373241205666815302
Coordinates: /execute in minecraft:overworld run tp @s -174800.35 61.00 -27463.65 -313.83 19.90

Steps to Reproduce:

1. Generate a world with the seed provided above and teleport to the given coordinates.
2. Look closely at the magma blocks.
3. Take note as to whether or not magma blocks can generate inside of icebergs.

Observed Behavior:

Magma blocks can generate inside of icebergs.

Expected Behavior:

Magma blocks would not be able to generate inside of icebergs.