In my personal opinion, this is one of the nature of altcoins. The altcoins may not always follow the hype of Bitcoin increase. Moreover, recently, Bitcoin price is still fluctuating and it still has high volatility. When the price of BTC is up, then altcoins are down because many investors prefer to sell their altcoins to get BTC. However, when the price of BTC has been more stable at a high rate, the altcoins have a great chance to keep increasing again.