There doesn't need to be some news on the press explaining sudden drops. Information is always asymmetrical, someone could have insider information and make a move before the rest go like sheep and sell, then the buy the dip. The very classic move in which market makers operate.
If anything, I saw that Jihan Wu left Bitmain, however that is positive news. Maybe someone related took a dump.
There's the possibility that is just a random whale cashing out for no reason, other than being closer to capitulation.
Also, information is always late, but not this late. There really was nothing that could be considered bad enough to trigger this flash crash, just as there wasn't anything good over a week ago to trigger that 10% spike (same jump, different direction).
The Jihan Wu rumours also were a week ago actually, and yeah, rumour mills always been busy but big investors do tend to react to that sort of anomalous news.
We should be used to this by now.