Block of grass appears too down in the caves.

I found many blocks of grass in a cave between layers 64 and y 49.

What actually happened was...:
I created a new munda in version 21w41a and while going in search of iron I found many blocks of grass in a cave .
Seed and Cordenades
Seed - 800344213203619290
Cordenades - X-189 Y-61 Z-137

 

Note : I had to translate by google translator