Villager Trading

There is a trading bug, where when a trade is maxed out, you get the emeralds, but also some of the raw material back. e.g. traded 64 coal for 4 emerald. Received 4 emeralds and then 16 coal dropped by villager which I can then pick up.

Please see video:
http://www.youtube.com/watch?v=Oy6qE4YcO_E

It's on my channel 'wefilmuwatch' if link fails.

Video shows other trades and some other curious features which you can check out. Need to watch all way through.