Error Grass minecraft 1.7.2

What I expected to happen was...:
When i was playing minecraft i found this bug of the grass i found how the grass are in the stone

What actually happened was...:
I quit 2 blocks and i found this bug

Steps to Reproduce:
1:Place a grass in a block
2:do a form like in the screenshots (3 screenshoot)
3:place a block in the side who you can see the grass and bug!
Sorry for mi bad english.im fron argentina
Nick of minecraft:TheIvanPro