This is the usual "sell the news" reaction by the traders. They buy on the way up, then assume that increases are baked in with the anticipation of news. They sell on the news, assuming that after a news release there will be a slow drift down for a while since there will be a long time between news releases. I think that the time interval to the next release may surprise them to the short side.

What's interesting here is to try to gauge the number of shares held by traders. The volume so far is actually low relative to recent action. Less than 2M shares so far- if that's all the shares in the hands of traders, then the float here has really decreased with the recent buying by presumably long term holders.