Yes, it's changed. The 1.7 BBF (Bronze Blast Furnace) isn't simply a bronze age version of the 1.6 EBF (Electric Blast Furnace). Putting lava inside in it will make the lava disappear, because lava blocks (not sources) are spawned inside it while it's working. Maybe you put the coal into the iron slot and vice versa, because, unlike in the EBF, in the BBF the order of placed item is really important.
I was playing with bronze age in 1.6.4 ..... Bronze age - "old" feature of gregtech. I did coal and coal dust, both in lower and upper slots. And nothing ... I tryed lava beacos just coal + iron didnt work