I wanted to place a torch in a hole on a roof. Made a 1x1 hole, covered from all sides except down, and when i placed there a torch, blocks around became black.

What I expected to happen was:
I expected normal "light" light from torch.

What actually happened was
Blocks around the torch became black.

Steps to Reproduce:
1. Place 3x3 blocks in 2 layers above yourself.
2. Remove central block in lower layer.
3. Place there a torch.

Hmm. Looks like Vanilla version of 1.4.6 not affected by this bug. Tested and worked with 1.4.6 + Minecraft Forge 6.5.0.471, both SSP and SMP (SMP launched from minecraft_server.jar)

Screenshots from 1 to 6 are showing SMP gameplay, 7-8 - SSP gameplay.