The difference between now and 312 is
312 incident: the market is declining every day, the exchange is paralyzed, and investors are about to collapse.
519 incident: the market fell to the ground in an instant, and the bottom was formed in three days. The whole market is shaky.
618 incident: the market has been falling all the way, dragging on for several weeks, and investors are in pain.
Now the market is still falling, it has been a whole month, and investors are about to become "fall experts".