Mycelium's side texture differs from other dirt-based blocks

The Bug

Mycelium blocks use a different dirt texture on the side than all other dirt based blocks.

MC-1483 was said to be fixed in this snapshot, but mycelium is still subject to it.

How To Reproduce:

1. Prepare a block of mycelium such that its side faces are clearly visible
2. Place a snow layer block on the top of this block, keeping a close eye on the general bottom right region of its side face
3. Note the texture changes which should not be
4. Remove the snow layer
5. Equip a shovel, paying attention to that same region of pixels
6. Transform the mycelium into a grass path by the defined key
7. Note that this also causes the pixels in question to change when they shouldn't
8. Repeat these tests, substituting the mycelium for either grass paths or podzol
9. Note the complete lack of randomly rearranging pixels in all cases