Found a bamboo shoot in a mountain biome that was near the appropriate biome, but it stood out.

What I expected to happen was...:
No bamboo in a mountain biome

What actually happened was...:
Bamboo in a mountain biome

Steps to Reproduce:
1. Start up Minecraft in the experimental 1.18 snapshot.
2. Generate a new world with the seed -2431823740702197355
3. Go to the coordinates -852 / 119 / -297

4. Observe bamboo.