Dirt doesn't grow grass when I'm not around

When sheep eat grass, it turns into dirt, and it's expected to turn back into grass no matter where you are. Regardless, when you're not nearby, the dirt won't grow grass.

What I expected to happen was:
The dirt to grow grass no matter how far away.

What actually happened was:
The dirt stayed like that forever, unless I was nearby.
And even if I am nearby, the grass grows extremely slower than pre0.8.0 versions.

Steps to Reproduce:
1. Go to an area where a lot of sheep are.
2. Look at the ground.
3. Go away for a few moments and come back to the area
4. Notice very little to no dirt has grown grass.