I am pretty sure it is just someone selling a ton of coins to drop for that exchange and then arbitrage people buying all of it to make it go back. It happens all the time in every single exchange, hell there was an instant where a trading bot mistakenly sold a ton of eth (or maybe bought, I forgot) and that was a big deal at the time, someone literally lost a ton of money because their trading bot screwed up.
I agree, maybe someone is trying to manipulate the price on that exchange and causes the massive spread on the price. Probably whales trying to trick investors and speculators.
Same could always happen, even if it is not trading bot, how much volume could there be in one exchange, even the biggest ones have only couple million at most to drop for a while, you can sell like 5 million dollars right away (5 mil worth btc of course) and drop the price, however arbitrage people will buy it right away to sell somewhere else and make a profit.
I was under the impression that arbitrage is dead already. But I could be wrong as people are really trying to make money here. So I wouldn't be surprise if some trading bot did it or just picking up the price. Good thing though is that the price remains relatively stable above $10,xxx.