Most people don’t understand that bank analysts (the people whose estimates get averaged for every “Apple beats estimates” headline) are complete jokes. Research departments are there to support the sale of bank services, and making management look amazing by having lowball estimates creates good relationship with the IB desks.
The markets trade on whisper numbers, which are what people with skin in the game are expecting. This is why you often see a name that beats estimates and drops...it’s because they missed the whisper numbers.
I doubt that this played a role here. Apple traded more or less flat over the quarter. If there were whisper numbers of even better results than what turned out to be a massively successful quarter, one should have seen the stock price go up significantly over the quarter.
It's common for many if not most companies. The guiding principle of buy on the rumor, sell on the news often means that a lot of investors realize gains after a big positive news event driving the price down. There were drops like that, iirc, when Apple announced the change to Intel and I think also the iPhone announcement. The drop is generally short-lived as the long-term investors buy in.