The Bug:

Decorations can generate on top of mossy cobblestone within old growth pine and spruce taiga biomes.

Just for clarification reasons, decoration blocks are blocks such as grass, ferns, brown mushrooms, etc...

Here is an example:

Seed: 4373241205666815302
Coordinates: /execute in minecraft:overworld run tp @s -22874.34 66.30 -21874.40 197.25 46.01

Steps to Reproduce:

1. Generate a world with the seed provided above and teleport to the given coordinates.
2. Look closely at the said decoration.
3. Take note as to whether or not decorations can generate on top of mossy cobblestone within old growth pine and spruce taiga biomes.

Observed Behavior:

Decorations can generate on top of mossy cobblestone.

Expected Behavior:

Decorations would not be able to generate on top of mossy cobblestone.