FallingSand - Only top side of block has a texture

In the newest snapshot there is a visual glitch if you use a command like this

/execute @e[type=WitherSkull] ~ ~ ~ summon FallingSand ~ ~0.6 ~ {TileID:23,Data:2,Time:0,DropItem:0,Motion:[0.0,0.04,0.0]}

to summon a FallingSand dispenser with a block infront of it. If you do this, only the top side of the blocks texture is visible, all other sides are not visible.

This did not happen in the snapshots before 14w25a.

This 11 second video shows what I mean:
Click me

Would be nice to have a fix for this, because I promised my viewers a solution on how I did this:
Link

Thanks!