Perusing around the Bug Reports here it seems that issue is still around in 0.0.71. It for some reason is remembering what ingot was in the middle anvil slot so when you place a single one it crafts a short blade out of the last material it remembers in that slot. I haven't used 0.0.7 but if the anvil has slots to put ingots, someone found a work around where you place your new ingot on the left, move it to the middle slot, and then you can move it back so that the game now remembers your new ingot as the last material in the middle slot. It has worked for me so far.
I have it from the developer himself that the bug has nothing to do with any particular slot. He said that if you want to make a short blade, just place the ingot in any slot, take it out, and put it back in that same slot.
You can actually just put it in the slot and right-click it (it should move toward you a little and snap back into the slot,) but I can understand the compulsion to lift it far away from the slot, or even put it in another one, just to make sure.