You can use pick-block on a smelting furnace and you will get a placeable forever-burning furnace.
Also, related to MC-7133, it has a bad texture in the inventory.
Middle mouse button on actived furnace wrong
When you middle-click on a furnace in cooking cycle (with flames), it gives you a bugged block with all faces identical
Picking up burning furnace block in creative has wrong texture
Selecting (on) furnace block instead of (off) furnace with scroll wheel.
"Pick Block" on burning furnace gives a burning furnace block
Texture of burning Furnace(ID62) shows no face in Inventory.