Probably those lower price where fix 30days ago, I guess the holders can replace their sell others and buy orders. It's a pro and con of steem-engine as many communities will lose some of their markets especially trader trading multiple currency who relies on data for explore, will be hard to keep track of entry prices and exit prices.

My advise to anyone trading on steem-engine is they should keep a hard record so if the others are canceled one can easily retrace his steps