Can't Place Torch on Top of Mob Spawner

SG Note 4

It is impossible to place torches on the top of the spawner block. Happens in both creative and survival. Crouching and trying to place the torch doesn't work either.

To reproduce:
1. Find or place a Monster Spawner block; it doesn't need to be active.
2. Place torches on the five exposed sides.
3. Torches will attach to the four vertical sides, but will not place on the horizontal top surface.