Flower map is inconsistant in the Y axis.

When generating flowers on Grass Blocks with Bonemeal, I get different flowers depending on the Y coordinate.

What I expected to happen was...:
As in earlier versions, I expected to get the same flowers at corresponding X and Z coordinates regardless of height in the world.

What actually happened was...:
Depending on height in the world (Y coordinate value) I get different flowers growing at the same same X and Z coordinates.

Steps to Reproduce:
1. Open an older version world in 1.18.2 OR create a fresh, new 1.18.2 world.
2. Create grass platforms in any biome at different heights directly above one another.
3. Bonemeal until flowers.
4. Observe the different flowers in frustration.