Without being an expert in these matters it could be that while the earnings were good they may have already been "priced in"[0], so if the earnings weren't quite as high as expected or particular areas of revenue have contracted unexpectedly[1] then it could cause the price to move downwards. It could also be a result of larger market fluctuations, as a lot of larger F100 companies have also gone down by a similar amount today[2]. Any one of these factors or a combination of them together is likely the cause of the stock price movement seen today.

[0] https://www.kotaksecurities.com/articles/it-is-priced-in-wha...

[1] https://finance.yahoo.com/news/alphabet-misses-expectations-...

[2] https://www.investors.com/market-trend/stock-market-today/do...