Put the summary of the bug you're having here
I Expected To Have Some Good Looking Half Grass.
Its Should Have Come Out As Some Swaggy looking grass.
The Other Half Came Out Like A
The Top Layer Of The Two Block High Grass Became For A Second A when i broke the lower bit.
How To Trigger The Bug
1. Find Some Grass
2. BoneMeal It So It Becomes Two Block High
3. Punch The Lower Bit