I really don't know enough of BTC developments to comment but my impression is that whatever angst BTC is going through is not clearcut as everyone would hope. See: https://en.bitcoin.it/wiki/Segwit_support suggests a bit of a mess.
If fiat is seen not to be as volatile, it seems crypto takes a hit in the way a safe haven would do. Certainly there seem to be big players or factors that affect a drop across all markets at the same time.. perhaps banking conspiracy to create more volatility at a time they would prefer to be in control. In the absence of obvious big news, it's hard to anticipate; so, best option is usually to ride it out. Low volume obviously also tempts exploitation.. the usual pump and dump looking for the naive to amplify those.