Resolution: Works As Intended
Minecraft 1.4.6, Minecraft 1.4.7, Snapshot 13w05b, Snapshot 13w06a
Windows 7 home premium, Service Pack 1
Java Recommended Version 7, Update 10
I can almost guarantee that this contains some duplicates, however, I would rather post all instances I found in one place than try and weed out the specific instances that have been reported already.
Blocks affected: Glass, Redstone Block, Glowstone, Slab, Stair
Blocks used for testing: Repeater, Door, Pressure Plate, Button, Lever (top, bottom, side), Rail, Ladder, Trapdoor, Torch (top, side), Flowerpot, Redstone Dust, Fire (top, bottom, side)
First image: Control. How we would expect blocks that must be attatched to other blocks to behave.
Glass: Non-solid block. Would expect it to support nothing, yet supports torches, just on top.
Redstone Block: Does not support Buttons or Ladders.
Glowstone: Supports only Redstone Dust and Trapdoor
Slab and Stair: Special case. Only thing I expected to work that did not is a lever on the bottom of a bottom slab/stair.