Its in anticipation of some of the new features that will be much improved over the original. Mintpal v2 will have real time feed, (no more f5 to refresh) and supposedly a host of other new features. Mintpal lost credibility with the whole Vericoin debacle and ultimately led to them being acquired by Moolah. As a result Bittrex rose in popularity, but has taken it on the chin with recent scam coins, ICO failures etc.
Its the typical "Buy on rumor, Sell on news" cycle that happens. The launch was supposed to be today but was postponed (again) until tues the 22nd. There was a slight dump as a result.
This has nothing to do with HAL, but I just have to correct this statement whenever I see it made. Moolah the company did not acquire Mintpal. It was the CEO of Moolah and two other anonymous individuals who financially acquired ownership of Mintpal. Moolah the company (aka Moopay LTD) was then contracted by the three owners of Mintpal to oversee the operations of the exchange.