Tell me the stock market is pretty efficient without telling me the stock market is efficient

From the WSJ:

Affirm closed down 21% at $58.68, a huge reversal from its performance earlier in the day, after the company accidentally tweeted some key quarterly results early. At one point, shares were up more than 12% at nearly $84…Investors initially cheered the abbreviated results, which seemed to punctuate Affirm’s breakout year [disclosing a 77% quarterly revenue jump and a big increase in transaction volume]…Investors were less impressed after they saw the full report, sending the shares down as much as 33% in afternoon trading. The company reported a wider loss in the latest quarter, and analysts raised concerns about the company’s profit margins and financial guidance.