When you place a torch on the floor if there is a wall next to the floor block, the torch will go onto the wall.

I expected the torch to place on the floor.

The torch placed on the wall.

How to reproduce
1. Build a tower 1 block wide and 2 blocks high.

2. Build the same tower 1 block away from it

3. Build on more tower the same size so that the corners of the towers are touching. Aerial view:
___________X
__________X_X
4. Place a torch on the floor between the towers.