I decided to re-report this cause mods are not re-opening MC-73397 despite the other screenshot I put. So, normal dirt (instead of coarse dirt) tends to generate on Savanna Plateau when tall grass is above it. I attached a screenshot to it.

NOTE: On the attached screenshot I have removed the tall grass above the thing so that you see its not coarse dirt.

Seed: -115225519156945386
Coordinates: x: -709 y: 93 z: 9