Grasless dirt generating instead of Coarse Dirt in Savanna Plateau

Well I was in a customized world exploring some biomes on 1.8 and I found some grassless dirt instead of coarse dirt in a Savanna Plateau biome. I re-made the world with default world type and the same happened. Strange because Coarse Dirt had replaced grassless dirt.

What I expected to happen was...:
Coarse dirt would generate

What actually happened was...:
Grasless dirt generated

Steps to Reproduce:
1. Go to a Savanna Plateau biome in 1.8.
2. Search for some grasless dirt
3. If you found it, then enjoy it.

If you don't want to follow the steps, then use this seed and coordinates:
Seed: -115225519156945386
Coordinates: x: -709 y: 93 z: 9