When a redstone torch is placed on the side, not top, of a block and the block is removed the redstone torch floats. The torch still functions, and you can put the block back without the torches breaking.
Environment
Windows 8, Java 7 64b bit, Intel i7 3.4 ghz, AMD Radeon 6800 series
63rd duplicate of MC-5711, please use the search function to see if your bug has already been submitted. Currently over 42% of tickets are being closed as duplicate.