on galaxy s6 - my furnaces stop smelting items when I leave to explore other places in my world. If I leave walk far enough away so that the furnace is in an unloaded chunk, the furnace stops processing. In mpce 14.3 and before when I would go several biomes away the furnace would have processed everything, but now when I come back it only has a few items. Seems to be that the furnace stops processing when the chunk it is in is unloaded. It smelts at regular speed when it is in an active chunk.