I've noticed it for a very long time: Bitcoin often has a stable price for a long time, then suddenly drops hard or shoots up. It dropped a few times in the past week, and as usual, it's very stable for a while after the drop. Yesterday's drop is no exception
this is typical of all markets. they're called range contraction and range expansion periods.
the two days of sideways after the selloff is usually called a bearish consolidation or bear flag because the subsequent range expansion usually continues in the direction of the original trend.
My guess is this is manipulation, and my next guess is someone is waiting for order books to be filled before placing another big sell (or buy) order which will cause the next price jump.
why does everyone around here assume manipulation is happening?

this kind of action can be completely organic IMO.