So in short, BlackRock has already been told and confirmed that their ETF will imminently approved, before everyone else's.

Someone then leaks it to a friend in Bloomberg, either to curry favor or to get in their pants. The friend can't help but break the news because he or she is a climber.

Price spikes and BR senior management's plan of hoarding at low cost while knowing (typical Wall Street inside trading behavior, don't be prudes) is thwarted, so they issue a retraction to cause a dip.

Depending how senior or smart the initial leaker was, he has made money twice today, and still will be able to buy on the cheap.