When I place a slab above a leaf block adjacent to a Grass Path Block, the leaf block should be visible through the small gap created by the path block. Instead, the leaf block dissapears, creating a visual "x-ray bug".

 
Steps to Reproduce:
1. Place a Grass Path, then, dig a 1x1 hole in any direction right next to it. Place an Oak Leaf Block in that slot you created.
2. Put a Slab Block above the Grass Block.
3. Notice that the Leaf Block can't be seen through the gap created by the Grass Path anymore.
Note: It only can be reproduced with the "Better Leaves" feature on. 

Added by Auldrick:
With Fancy Leaves turned on. Affects all species of leaves. The slab can be a bottom slab, top slab, or double slab. When a top slab is used, the top texture of the leaves is rendered. The side texture is not rendered at all, so the sky can be seen above the grass path.