So, as someone who knows a tiny bit about market dynamics we could just be seeing someone who acrued a significant fortune in bitcoin selling it all at once.
When you're managing a hedge fund or a very large portfolio you have to sell in small segments or you could temporary depress the trading price or even cause a market crisis where other people think you know something they don't and decide to sell too.
It's probably nothing.
I'm not super familiar with bitcoin markets, but if you have anything like level 2 stock market access you should be able to check my theory by seeing if the trades are coming majorly from a single wallet or associated wallets.
Maybe Satoshi wants to buy a private island and needs to cash out some of his coins?