Possible ABC correction wave within the flag.
Looking at it in this perspective makes what happened on the 18th look like not-a-big-deal.
If this pattern holds I would expect the to start moving up and eventually cross in the next few days.
It's currently riding just below the 20 day . At the beginning of April it crossed above the 20 day and used it as launching pad.
BCD/BTC has made explosive moves in the past so when it moves expect fireworks.