What I expected:
When trying to place a torch on a wall while looking at the ceiling block next to it, the torch should be automatically placed on the wall, nothing more, nothing less.

What happened:
When I placed a torch on a ceiling block next to a wall, a mob head with unknown texture (you know, that classic black-purple checked texture) appeared instead of the torch (at least it seemed to be a mob head)
-EDIT:
The bug seems to be caused when you are trying to place a torch on a block where it can´t be placed (and can be placed next to it), e.g. trying to place a torch on glass in the corner of the room makes the torch to be placed on a non-transparent block next to the glass block, causing the same bug as the ceiling replace.
Also added a new screenshot with this situation.

Steps to Reproduce:
1. Look at a ceiling block next to a wall made of any block (that can hold torches)
2. Place a torch on the ceiling block
3. A mob head with missing texture appears on the wall instead of the torch, it disappears after a split second, then a torch will be normally placed on the wall.

Some Screenshots Included.
Map info in comments.

Sorry for so much edits, only the listed one is "breakthrough".
Ladislav Bielko AKA Terry125