This is not the bug that when you pick block a burning furnace you get a regular furnace. (Personally I do not believe that is a bug)

If you ctrl+pick block a burning furnace in the latest snapshots, the burning furnace texture doesn't show, even though if you look in the furnace you see the operation going.

What I thought would happen: I would ctrl+pick block a burning furnace, place it, and I would see the burning furnace texture and see the operation running.

What happened: I ctrl+pick blocked a burning furnace and I placed it, but I didn't see the burning furnace texture, even though the furnace was working when I looked inside.

How to reproduce:
1. Open up or create a creative world in 14w07a or 14w08a (Might also work in later versions, those are the most recent at the time of writing.)
2.Get a furnace, some fuel, and something to be smelted.
3. Place the furnace and put the stuff into it.
4. Ctrl+pick block it and place it.
5. You should see a normal furnace texture but see the operation taking place inside.